Moved supported versions into ProxyConstants

This reverts commit 6361c0e8e9.

.github/ISSUE_TEMPLATE/config.yml

@@ -0,0 +1,8 @@
+blank_issues_enabled: false
+contact_links:
+  - name: Auxilor Community Discord
+    url: https://discord.gg/ZcwpSsE/
+    about: Join the Auxilor discord to get help from support staff and the general community!
+  - name: The most common issues people have
+    url: https://github.com/Auxilor/eco/issues/78
+    about: Check the list of known common issues to see if your issue has already been solved

.github/ISSUE_TEMPLATE/report-a-bug.md

@@ -0,0 +1,31 @@
+---
+name: Report a Bug
+about: Report an issue with the plugin
+title: ''
+labels: bug
+assignees: ''
+
+---
+
+**Describe the bug**
+A clear and concise description of what the bug is.
+
+**To Reproduce**
+Steps to reproduce the behavior: 
+1. Go to '...'
+2. Click on '....'
+3. Scroll down to '....'
+4. See error
+
+**Expected behavior**
+A clear and concise description of what you expected to happen.
+
+**Screenshots**
+If applicable, add screenshots to help explain your problem.
+
+**Server Information (please complete the following information):**
+- Version: (output of `/ver` command)
+- Version of plugin and eco (`/ver eco`, `/ver <plugin>`)
+
+**Additional context**
+Add any other context about the problem here.

.github/ISSUE_TEMPLATE/request-a-feature.md

@@ -0,0 +1,20 @@
+---
+name: Request a Feature
+about: Suggest an idea for this plugin
+title: ''
+labels: enhancement
+assignees: ''
+
+---
+
+**Is your feature request related to a problem? Please describe.**
+A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
+
+**Describe the solution you'd like**
+A clear and concise description of what you want to happen.
+
+**Describe alternatives you've considered**
+A clear and concise description of any alternative solutions or features you've considered.
+
+**Additional context**
+Add any other context or screenshots about the feature request here.

.github/dependabot.yml

@@ -0,0 +1,11 @@
+# To get started with Dependabot version updates, you'll need to specify which
+# package ecosystems to update and where the package manifests are located.
+# Please see the documentation for all configuration options:
+# https://help.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+
+version: 2
+updates:
+  - package-ecosystem: "gradle" # See documentation for possible values
+    directory: "/" # Location of package manifests
+    schedule:
+      interval: "daily"

.github/workflows/checkstyle.yml

@@ -0,0 +1,15 @@
+name: Check PR Codestyle
+on: [ pull_request ]
+
+jobs:
+  checkstyle:
+    name: Checkstyle
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: dbelyaev/action-checkstyle@v0.5.1
+        with:
+          github_token: ${{ secrets.github_token }}
+          reporter: github-pr-review
+          level: warning
+          checkstyle_config: ../../config/checkstyle/checkstyle.xml

.github/workflows/java-ci.yml

@@ -0,0 +1,36 @@
+name: Java CI
+
+on: [ push, pull_request ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout latest code
+        uses: actions/checkout@v2
+
+      - name: Set outputs
+        id: vars
+        run: echo "::set-output name=sha_short::$(git rev-parse --short HEAD)"
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v2
+        with:
+          distribution: 'temurin'
+          java-version: 17
+
+      - name: Setup build cache
+        uses: actions/cache@v2.1.6
+        with:
+          path: ~/.gradle/caches
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle.kts') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+
+      - run: ./gradlew build --full-stacktrace
+
+      - uses: actions/upload-artifact@v2
+        with:
+          name: eco-dev-${{ steps.vars.outputs.sha_short }}
+          path: build/libs

.github/workflows/publish-release.yml

@@ -0,0 +1,38 @@
+name: Publish release
+
+on:
+  release:
+    types: [published]
+
+jobs:
+  publish-release:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout latest code
+        uses: actions/checkout@v2
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v2
+        with:
+          distribution: 'temurin'
+          java-version: 17
+
+      - name: Setup build cache
+        uses: actions/cache@v2.1.6
+        with:
+          path: ~/.gradle/caches
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle.kts') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+      - name: Publish artifact
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+        # The GITHUB_REF tag comes in the format 'refs/tags/xxx'.
+        # So if we split on '/' and take the 3rd value, we can get the release name.
+        run: |
+          NEW_VERSION=$(echo "${GITHUB_REF}" | cut -d "/" -f3)
+          echo "New version: ${NEW_VERSION}"
+          echo "Github username: ${GITHUB_ACTOR}"
+          ./gradlew -Pversion=${NEW_VERSION} publish

.github/workflows/test-publish.yml

@@ -0,0 +1,42 @@
+name: Publish API (Dev)
+
+on: [ push, pull_request ]
+
+jobs:
+  publish-release:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout latest code
+        uses: actions/checkout@v2
+
+      - name: Set outputs
+        id: vars
+        run: echo "::set-output name=sha_short::$(git rev-parse --short HEAD)"
+
+      - name: Set up JDK 17
+        uses: actions/setup-java@v2
+        with:
+          distribution: 'temurin'
+          java-version: 17
+
+      - name: Setup build cache
+        uses: actions/cache@v2.1.6
+        with:
+          path: ~/.gradle/caches
+          key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle.kts') }}
+          restore-keys: |
+            ${{ runner.os }}-gradle-
+
+
+      - name: Publish artifact
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+        # The GITHUB_REF tag comes in the format 'refs/tags/xxx'.
+        # So if we split on '/' and take the 3rd value, we can get the release name.
+        run: |
+          NEW_VERSION=$(echo "${GITHUB_REF}" | cut -d "/" -f3)
+          echo "New version: ${{ steps.vars.outputs.sha_short }}"
+          echo "Github username: ${GITHUB_ACTOR}"
+          ./gradlew -Pversion=dev-${{ steps.vars.outputs.sha_short }} publish

.gitignore

@@ -14,7 +14,8 @@ bin/
 # Gradle
 .gradle
 **/build/
-!src/**/build/
+**/out/
+!eco-api/src/**/build/
 .gradletasknamecache
 !gradle-wrapper.jar
 gradle-app.setting

CONTRIBUTING.md

@@ -1,27 +1,38 @@
 # How to contribute to eco
 
 ## Codestyle
+
 1. The eco checkstyle is in /config/checkstyle.xml
+
 - The pull request must not have any checkstyle issues.
 - Every method and field must have a javadoc attached.
 
-2. Use lombok wherever possible.
+2. Use JetBrains annotations
-- @Getter, @Setter, @ToString, @EqualsAndHashCode, @UtilityClass are the most important.
 
-3. Use JetBrains annotations
 - Every parameter should be annotated with @NotNull or @Nullable
-- Use @NotNull over lombok @NonNull
 
-4. Imports
+3. Imports
+
 - No group (*) imports.
 - No static imports.
 
+4. Kotlin
+
+- Kotlin should be the only language used in the backend, java should be the only language used in the frontend.
+- Kotlin API extensions should only be for creating extension functions and extra niceties that aren't possible in java.
+  Do not write API components in kotlin.
+- Kotlin code should never be called directly from the frontend Java API. Kotlin API extensions should always rely on
+  java, not the other way round.
+
 ## Dependency Injection
+
 - eco uses Dependency Injection
-- Any calls to AbstractEcoPlugin#getInstance are code smells and should never be used unless **absolutely necessary**.
+- Any calls to Eco#getHandler#getEcoPlugin are code smells and should never be used unless **absolutely necessary**.
 - NamespacedKeys, FixedMetadataValues, Runnables, and Schedules should be managed using AbstractEcoPlugin through DI.
-- Any DI class should extend PluginDependent where possible. If the class extends another, then you **must** store the plugin instance in a private final variable called **plugin** with a private or protected getter.
+- Any DI class should extend PluginDependent where possible. If the class extends another, then you **must** store the
+  plugin instance in a private final variable called **plugin** with a private or protected getter.
 
 ## Other
+
 - All drops **must** be sent through a DropQueue - calls to World#dropItem will get your PR rejected.
-- eco is built with java 8. Usage of J9+ will get your PR rejected.
+- eco is built with java 17.

README.md

@@ -1 +1,121 @@
-## eco - Library for spigot plugin development.
+# eco
+eco is a powerful Spigot development library that simplifies the process of plugin creation and supercharges
+your plugins.
+It's the engine behind [EcoEnchants](https://polymart.org/resource/490), [Reforges](https://polymart.org/resource/1330),
+[EcoItems](https://polymart.org/resource/1247), [EcoSkills](https://polymart.org/resource/1351),
+[EcoArmor](https://polymart.org/resource/687), [Talismans](https://polymart.org/resource/611),
+and many more.
+
+<p>
+    <a href="https://github.com/Auxilor/eco/releases">
+        <img alt="spigot" src="https://img.shields.io/github/v/release/Auxilor/eco?color=informational"/>
+    </a>
+    <a href="https://bstats.org/plugin/bukkit/EcoEnchants" alt="bstats servers">
+        <img src="https://img.shields.io/bstats/servers/7666?color=informational"/>
+    </a>
+    <a href="https://bstats.org/plugin/bukkit/EcoEnchants" alt="bstats players">
+        <img src="https://img.shields.io/bstats/players/7666?color=informational"/>
+    </a>
+    <a href="https://plugins.auxilor.io/" alt="Docs (gitbook)">
+        <img src="https://img.shields.io/badge/docs-gitbook-informational"/>
+    </a>
+    <a href="https://discord.gg/ZcwpSsE/" alt="Discord">
+        <img src="https://img.shields.io/discord/452518336627081236?label=discord&color=informational"/>
+    </a>
+    <a href="https://github.com/Auxilor/eco/actions/workflows/java-ci.yml" alt="Latest Dev Build">
+        <img src="https://img.shields.io/github/workflow/status/Auxilor/eco/Java%20CI/develop?color=informational"/>
+    </a>
+</p>
+
+# For server owners
+- Requires ProtocolLib to be installed: get the latest version [here](https://www.spigotmc.org/resources/protocollib.1997/)
+- Supports 1.17+
+
+## Downloads
+
+- Stable (Recommended): [GitHub](https://github.com/Auxilor/eco/releases), [Polymart](https://polymart.org/resource/eco.773)
+- Dev (Not Recommended): [GitHub](https://github.com/Auxilor/eco/actions/workflows/java-ci.yml) (Open latest run and download)
+
+# For developers
+
+## Javadoc
+The 6.13.0 Javadoc can be found [here](https://javadoc.jitpack.io/com/willfp/eco/6.13.0/javadoc/)
+
+## Plugin Information
+
+eco is a standalone plugin, so you will need to install it on any servers that have plugins which depend on it,
+and specify it as a dependency in your plugin.yml:
+
+```yaml
+depend:
+  - eco
+```
+
+## Get from JitPack:
+
+Gradle:
+
+```groovy
+repositories {
+        maven { url 'https://jitpack.io' }
+}
+
+```
+
+```groovy
+dependencies {
+        compileOnly 'com.willfp:eco:Tag'
+}
+```
+
+Replace `Tag` with a release tag for eco, eg `6.13.0`.
+
+Maven:
+
+```xml
+<repository>
+        <id>jitpack.io</id>
+        <url>https://jitpack.io</url>
+</repository>
+```
+
+```xml
+<dependency>
+        <groupId>com.willfp</groupId>
+        <artifactId>eco</artifactId>
+        <version>Tag</version>
+        <scope>provided</scope>
+</dependency>
+```
+
+Replace `Tag` with a release tag for eco, eg `6.13.0`.
+
+## Build locally:
+
+Run the following commands in your terminal of choice.
+
+If you're on windows, you will need to have git bash installed.
+```
+git clone https://github.com/Auxilor/eco
+cd eco
+./gradlew build
+```
+
+## License
+
+*Click here to read [the entire license](https://github.com/Auxilor/eco/blob/master/LICENSE.md).*
+
+<h1 align="center">
+  Check out our partners!
+  <br>
+  <div style="width: 50%; margin: 0 auto;">
+  <br>
+    <a href="https://gamersupps.gg/discount/Auxilor?afmc=Auxilor" target="_blank">
+      <img src="https://i.imgur.com/7mFhlQO.png" alt="supps banner">
+    </a>
+    <a href="https://dedimc.promo/Auxilor" target="_blank">
+      <img src="https://i.imgur.com/x9aeH38.png" alt="dedimc banner">
+    </a>
+  <br>
+  </div>
+</h1>

build.gradle

@@ -1,102 +0,0 @@
-plugins {
-    id 'java-library'
-    id 'com.github.johnrengelman.shadow' version '5.2.0'
-    id 'maven-publish'
-    id 'java'
-}
-
-dependencies {
-    implementation 'org.apache.maven:maven-artifact:3.0.3'
-    implementation 'org.bstats:bstats-bukkit:1.7'
-    compileOnly 'org.spigotmc:spigot-api:1.16.4-R0.1-SNAPSHOT'
-    compileOnly 'me.clip:placeholderapi:2.10.9'
-    compileOnly 'com.comphenix.protocol:ProtocolLib:4.6.0-SNAPSHOT'
-    compileOnly 'com.sk89q.worldguard:worldguard-bukkit:7.0.4-SNAPSHOT'
-    compileOnly 'com.github.TechFortress:GriefPrevention:16.14.0'
-    compileOnly 'com.massivecraft:Factions:1.6.9.5-U0.5.10'
-    compileOnly 'com.github.cryptomorin:kingdoms:1.10.3.1'
-    compileOnly 'com.github.TownyAdvanced:Towny:0.96.2.0'
-    compileOnly 'com.github.angeschossen:LandsAPI:4.7.3'
-    compileOnly 'fr.neatmonster:nocheatplus:3.16.1-SNAPSHOT'
-    compileOnly 'com.github.jiangdashao:matrix-api-repo:317d4635fd'
-    compileOnly 'org.jetbrains:annotations:19.0.0'
-    compileOnly fileTree(dir: '/lib', include: ['*.jar'])
-
-    // Lombok
-    compileOnly 'org.projectlombok:lombok:1.18.16'
-    annotationProcessor 'org.projectlombok:lombok:1.18.16'
-    testCompileOnly 'org.projectlombok:lombok:1.18.16'
-    testAnnotationProcessor 'org.projectlombok:lombok:1.18.16'
-}
-
-
-repositories {
-    mavenCentral()
-    jcenter()
-    mavenLocal()
-    maven { url 'https://jitpack.io' }
-
-    // NMS (for jitpack compilation)
-    maven { url 'https://repo.codemc.org/repository/nms/' }
-
-    // bStats
-    maven { url 'https://repo.codemc.org/repository/maven-public' }
-
-    // Spigot API
-    maven { url 'https://hub.spigotmc.org/nexus/content/repositories/snapshots/' }
-
-    // PlaceholderAPI
-    maven { url 'https://repo.extendedclip.com/content/repositories/placeholderapi/' }
-
-    // ProtocolLib
-    maven { url 'https://repo.dmulloy2.net/nexus/repository/public/' }
-
-    // WorldGuard
-    maven { url 'https://maven.enginehub.org/repo/' }
-
-    // FactionsUUID
-    maven { url 'https://ci.ender.zone/plugin/repository/everything/' }
-
-    // NoCheatPlus
-    maven { url 'https://repo.md-5.net/content/repositories/snapshots/' }
-}
-
-tasks.withType(JavaCompile) {
-    options.deprecation = true
-    options.encoding = 'UTF-8'
-}
-
-configurations.all {
-    exclude group: "org.codehaus.plexus", module: "plexus-utils"
-    exclude group: "com.mojang", module: "brigadier"
-    exclude group: "org.kitteh", module: "paste-gg-api"
-    exclude group: "org.spongepowered", module: "configurate-hocon"
-    exclude group: "com.darkblade12", module: "particleeffect"
-}
-
-shadowJar {
-    relocate('org.bstats.bukkit', 'com.willfp.eco.util.shaded.bstats')
-    relocate('org.apache.maven', 'com.willfp.eco.util.shaded.maven')
-}
-
-publishing {
-    publications {
-        shadow(MavenPublication) {
-            from components.java
-            artifact shadowJar
-        }
-    }
-}
-
-compileJava.options.encoding = 'UTF-8'
-compileJava.dependsOn clean
-
-publishToMavenLocal.dependsOn shadowJar
-
-build.dependsOn shadowJar
-build.dependsOn publishToMavenLocal
-
-group = 'com.willfp'
-archivesBaseName = project.name
-version = '1.0.1'
-java.sourceCompatibility = JavaVersion.VERSION_1_8

build.gradle.kts

@@ -0,0 +1,163 @@
+buildscript {
+    repositories {
+        mavenCentral()
+    }
+
+    dependencies {
+        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:1.6.10")
+    }
+}
+
+plugins {
+    id("java-library")
+    id("com.github.johnrengelman.shadow") version "7.1.2"
+    id("maven-publish")
+    id("java")
+    kotlin("jvm") version "1.6.10"
+}
+
+dependencies {
+    implementation(project(":eco-api"))
+    implementation(project(":eco-core:core-plugin"))
+    implementation(project(":eco-core:core-proxy"))
+    implementation(project(":eco-core:core-backend"))
+    implementation(project(path = ":eco-core:core-nms:v1_17_R1", configuration = "reobf"))
+    implementation(project(path = ":eco-core:core-nms:v1_18_R1", configuration = "reobf"))
+}
+
+allprojects {
+    apply(plugin = "java")
+    apply(plugin = "java-library")
+    apply(plugin = "maven-publish")
+    apply(plugin = "com.github.johnrengelman.shadow")
+    apply(plugin = "kotlin")
+
+    repositories {
+        mavenCentral()
+        mavenLocal()
+        maven("https://jitpack.io")
+
+        // CustomCrafting
+        maven("https://maven.wolfyscript.com/repository/public/")
+
+        // SuperiorSkyblock2
+        maven("https://repo.bg-software.com/repository/api/")
+
+        // NMS (for jitpack compilation)
+        maven("https://repo.codemc.org/repository/nms/")
+
+        // mcMMO, BentoBox
+        maven("https://repo.codemc.org/repository/maven-public/")
+
+        // Spigot API, Bungee API
+        maven("https://hub.spigotmc.org/nexus/content/repositories/snapshots/")
+
+        // PlaceholderAPI
+        maven("https://repo.extendedclip.com/content/repositories/placeholderapi/")
+
+        // ProtocolLib
+        maven("https://repo.dmulloy2.net/nexus/repository/public/")
+
+        // WorldGuard
+        maven("https://maven.enginehub.org/repo/")
+
+        // FactionsUUID
+        maven("https://ci.ender.zone/plugin/repository/everything/")
+
+        // NoCheatPlus
+        maven("https://repo.md-5.net/content/repositories/snapshots/")
+
+        // CombatLogX
+        maven("https://nexus.sirblobman.xyz/repository/public/")
+
+        // IridiumSkyblock
+        maven("https://nexus.iridiumdevelopment.net/repository/maven-releases/")
+
+        // MythicMobs
+        maven("https://mvn.lumine.io/repository/maven-public/")
+
+        // Crunch
+        maven("https://redempt.dev")
+
+        // LibsDisguises
+        maven("https://repo.md-5.net/content/groups/public/")
+    }
+
+    dependencies {
+        compileOnly(kotlin("stdlib", version = "1.6.10"))
+        compileOnly("org.jetbrains:annotations:23.0.0")
+
+        // Test
+        testImplementation("org.junit.jupiter:junit-jupiter-api:5.8.2")
+        testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:5.8.2")
+        
+        // Adventure
+        compileOnly("net.kyori:adventure-api:4.9.3")
+        compileOnly("net.kyori:adventure-text-serializer-gson:4.9.3")
+        compileOnly("net.kyori:adventure-text-serializer-legacy:4.9.3")
+
+        // Other
+        compileOnly("com.google.guava:guava:31.0.1-jre")
+        compileOnly("com.github.ben-manes.caffeine:caffeine:3.0.5")
+    }
+
+    tasks.withType<JavaCompile> {
+        options.encoding = "UTF-8"
+    }
+
+    configurations.all {
+        exclude(group = "org.codehaus.plexus", module = "plexus-utils")
+        exclude(group = "com.mojang", module = "brigadier")
+        exclude(group = "org.kitteh", module = "paste-gg-api")
+        exclude(group = "org.kitteh", module = "pastegg")
+        exclude(group = "org.spongepowered", module = "configurate-hocon")
+        exclude(group = "com.darkblade12", module = "particleeffect")
+        exclude(group = "com.github.cryptomorin", module = "XSeries")
+    }
+
+    configurations.testImplementation {
+        setExtendsFrom(listOf(configurations.compileOnly.get()))
+    }
+
+    tasks {
+        compileKotlin {
+            kotlinOptions {
+                jvmTarget = "17"
+            }
+            targetCompatibility = "17"
+            sourceCompatibility = "17"
+        }
+
+        shadowJar {
+            relocate("org.bstats", "com.willfp.eco.shaded.bstats")
+            relocate("net.kyori.adventure.text.minimessage", "com.willfp.eco.shaded.minimessage")
+        }
+
+        compileJava {
+            dependsOn(clean)
+            options.encoding = "UTF-8"
+        }
+
+        java {
+            sourceCompatibility = JavaVersion.VERSION_17
+            targetCompatibility = JavaVersion.VERSION_17
+            withSourcesJar()
+        }
+
+        test {
+            useJUnitPlatform()
+
+            // Show test results.
+            testLogging {
+                events("passed", "skipped", "failed")
+            }
+        }
+
+        build {
+            dependsOn(shadowJar)
+        }
+    }
+}
+
+group = "com.willfp"
+version = findProperty("version")!!

config/checkstyle/checkstyle.xml

@@ -32,10 +32,6 @@
 -->
 
 <module name="Checker">
-    <module name="SuppressionFilter">
-        <property name="file" value="config/checkstyle/suppression.xml"/>
-    </module>
-
     <!--
         If you set the basedir property below, then all reported file
         names will be relative to the specified directory. See
@@ -45,7 +41,7 @@
     -->
     <property name="severity" value="error"/>
 
-    <property name="fileExtensions" value="java, properties, xml"/>
+    <property name="fileExtensions" value="java, properties, xml, kt"/>
 
     <!-- Excludes all 'module-info.java' files              -->
     <!-- See https://checkstyle.org/config_filefilters.html -->
@@ -66,6 +62,7 @@
     <module name="FileLength"/>
     <module name="LineLength">
         <property name="fileExtensions" value="java"/>
+        <property name="fileExtensions" value="kt"/>
         <property name="max" value="200"/>
     </module>
 
@@ -115,7 +112,6 @@
         <!-- Checks for imports                              -->
         <!-- See https://checkstyle.org/config_imports.html -->
         <module name="AvoidStarImport"/>
-        <module name="IllegalImport"/> <!-- defaults to sun.* packages -->
         <module name="RedundantImport"/>
         <module name="UnusedImports">
             <property name="processJavadoc" value="true"/>

config/checkstyle/suppression.xml

@@ -1,16 +0,0 @@
-<?xml version="1.0"?>
-
-<!DOCTYPE suppressions PUBLIC
-        "-//Puppy Crawl//DTD Suppressions 1.1//EN"
-        "http://www.puppycrawl.com/dtds/suppressions_1_1.dtd">
-
-<suppressions>
-    <!-- Modified version of library -->
-    <suppress files="ArmorEquipEvent.java" checks="JavadocVariable"/>
-    <suppress files="ArmorEquipEvent.java" checks="MissingJavadocMethod"/>
-    <suppress files="ArmorEquipEvent.java" checks="JavadocStyle"/>
-    <suppress files="ArmorListener.java" checks="JavadocVariable"/>
-    <suppress files="ArmorListener.java" checks="MissingJavadocMethod"/>
-    <suppress files="ArmorType.java" checks="JavadocVariable"/>
-    <suppress files="ArmorType.java" checks="MissingJavadocMethod"/>
-</suppressions>

eco-api/build.gradle

@@ -0,0 +1,36 @@
+dependencies {
+    // Adventure
+    compileOnly 'net.kyori:adventure-platform-bukkit:4.0.0'
+    compileOnly 'net.kyori:adventure-text-minimessage:4.1.0-SNAPSHOT'
+
+    // Other
+    compileOnly 'org.spigotmc:spigot-api:1.17.1-R0.1-SNAPSHOT'
+    compileOnly 'org.apache.maven:maven-artifact:3.8.1'
+    compileOnly 'com.comphenix.protocol:ProtocolLib:4.6.1-SNAPSHOT'
+    compileOnly 'com.google.code.gson:gson:2.8.8'
+}
+
+group 'com.willfp'
+version rootProject.version
+
+build.dependsOn publishToMavenLocal
+
+publishing {
+    publications {
+        shadow(MavenPublication) {
+            from components.java
+            artifactId 'eco'
+        }
+    }
+
+    repositories {
+        maven {
+            name = "GitHubPackages"
+            url = uri("https://maven.pkg.github.com/Auxilor/eco")
+            credentials {
+                username = System.getenv("GITHUB_ACTOR")
+                password = System.getenv("GITHUB_TOKEN")
+            }
+        }
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/AbstractPacketAdapter.java

@@ -1,4 +1,4 @@
-package com.willfp.eco.util.protocollib;
+package com.willfp.eco.core;
 
 import com.comphenix.protocol.PacketType;
 import com.comphenix.protocol.ProtocolLibrary;
@@ -6,12 +6,14 @@ import com.comphenix.protocol.events.ListenerPriority;
 import com.comphenix.protocol.events.PacketAdapter;
 import com.comphenix.protocol.events.PacketContainer;
 import com.comphenix.protocol.events.PacketEvent;
-import com.willfp.eco.util.plugin.AbstractEcoPlugin;
+import org.bukkit.entity.Player;
-import lombok.Getter;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.Collections;
 
+/**
+ * Wrapper class for ProtocolLib packets.
+ */
 public abstract class AbstractPacketAdapter extends PacketAdapter {
     /**
      * The packet type to listen for.
@@ -23,7 +25,6 @@ public abstract class AbstractPacketAdapter extends PacketAdapter {
      * <p>
      * Useful for monitor priority adapters that <b>must</b> be ran last.
      */
-    @Getter
     private final boolean postLoad;
 
     /**
@@ -34,7 +35,7 @@ public abstract class AbstractPacketAdapter extends PacketAdapter {
      * @param priority The priority at which the adapter should be ran on packet send/receive.
      * @param postLoad If the packet adapter should be registered after the server has loaded.
      */
-    protected AbstractPacketAdapter(@NotNull final AbstractEcoPlugin plugin,
+    protected AbstractPacketAdapter(@NotNull final EcoPlugin plugin,
                                     @NotNull final PacketType type,
                                     @NotNull final ListenerPriority priority,
                                     final boolean postLoad) {
@@ -50,7 +51,7 @@ public abstract class AbstractPacketAdapter extends PacketAdapter {
      * @param type     The {@link PacketType} to listen for.
      * @param postLoad If the packet adapter should be registered after the server has loaded.
      */
-    protected AbstractPacketAdapter(@NotNull final AbstractEcoPlugin plugin,
+    protected AbstractPacketAdapter(@NotNull final EcoPlugin plugin,
                                     @NotNull final PacketType type,
                                     final boolean postLoad) {
         this(plugin, type, ListenerPriority.NORMAL, postLoad);
@@ -60,8 +61,12 @@ public abstract class AbstractPacketAdapter extends PacketAdapter {
      * The code that should be executed once the packet has been received.
      *
      * @param packet The packet.
+     * @param player The player.
+     * @param event  The event.
      */
-    public void onReceive(@NotNull final PacketContainer packet) {
+    public void onReceive(@NotNull final PacketContainer packet,
+                          @NotNull final Player player,
+                          @NotNull final PacketEvent event) {
         // Empty rather than abstract as implementations don't need both
     }
 
@@ -69,8 +74,12 @@ public abstract class AbstractPacketAdapter extends PacketAdapter {
      * THe code that should be executed once the packet has been sent.
      *
      * @param packet The packet.
+     * @param player The player.
+     * @param event  The event.
      */
-    public void onSend(@NotNull final PacketContainer packet) {
+    public void onSend(@NotNull final PacketContainer packet,
+                       @NotNull final Player player,
+                       @NotNull final PacketEvent event) {
         // Empty rather than abstract as implementations don't need both
     }
 
@@ -89,7 +98,7 @@ public abstract class AbstractPacketAdapter extends PacketAdapter {
             return;
         }
 
-        onReceive(event.getPacket());
+        onReceive(event.getPacket(), event.getPlayer(), event);
     }
 
     /**
@@ -107,7 +116,12 @@ public abstract class AbstractPacketAdapter extends PacketAdapter {
             return;
         }
 
-        onSend(event.getPacket());
+        onSend(event.getPacket(), event.getPlayer(), event);
+    }
+
+    @Override
+    public final EcoPlugin getPlugin() {
+        return (EcoPlugin) super.getPlugin();
     }
 
     /**
@@ -118,4 +132,13 @@ public abstract class AbstractPacketAdapter extends PacketAdapter {
             ProtocolLibrary.getProtocolManager().addPacketListener(this);
         }
     }
+
+    /**
+     * Get if the packet adapter should be loaded last.
+     *
+     * @return If post load.
+     */
+    public boolean isPostLoad() {
+        return this.postLoad;
+    }
 }

eco-api/src/main/java/com/willfp/eco/core/Eco.java

@@ -0,0 +1,82 @@
+package com.willfp.eco.core;
+
+import org.apache.commons.lang.Validate;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Holds the instance of the eco handler for bridging between the frontend
+ * and backend.
+ *
+ * @see Eco#getHandler()
+ * @see Handler
+ */
+@ApiStatus.Internal
+public final class Eco {
+    /**
+     * Instance of eco handler.
+     */
+    @ApiStatus.Internal
+    private static Handler handler;
+
+    /**
+     * Set the handler.
+     *
+     * @param handler The handler.
+     */
+    @ApiStatus.Internal
+    public static void setHandler(@NotNull final Handler handler) {
+        Validate.isTrue(Eco.handler == null, "Already initialized!");
+
+        Eco.handler = handler;
+    }
+
+    /**
+     * Get the instance of the eco handler; the bridge between the api frontend
+     * and the implementation backend.
+     * <p>
+     * <strong>Do not use the handler in your plugins!</strong> It can and will contain
+     * breaking changes between minor versions and even patches, and you will create
+     * compatibility issues by using the handler. All parts of the handler have been abstracted
+     * into logically named API components that you can use.
+     * <p>
+     * Prior to version 6.12.0, the handler was considered as an API component, but it has
+     * since been moved into an internal component, and in 6.17.0, the first breaking change
+     * was introduced to {@link com.willfp.eco.core.config.wrapper.ConfigFactory}. This means
+     * that any usages of the handler can now cause problems in your plugins.
+     *
+     * @return The handler.
+     */
+    @ApiStatus.Internal
+    public static Handler getHandler() {
+        return handler;
+    }
+
+    /**
+     * Eco Handler components are internals, so if a class is marked as a handler component,
+     * then it should be treated the same as if it was marked with {@link ApiStatus.Internal}.
+     * <p>
+     * If a class is marked with {@link HandlerComponent}, <strong>Do not reference it in
+     * your code!</strong> It can and will contain breaking changes between minor versions and
+     * even patches, and you will create compatibility issues by using them.
+     * <p>
+     * Handler components should also be marked with {@link ApiStatus.Internal} in order to
+     * cause compiler / IDE warnings.
+     */
+    @Documented
+    @Retention(RetentionPolicy.CLASS)
+    @Target({ElementType.TYPE})
+    public @interface HandlerComponent {
+
+    }
+
+    private Eco() {
+        throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/EcoPlugin.java

@@ -0,0 +1,921 @@
+package com.willfp.eco.core;
+
+import com.willfp.eco.core.command.impl.PluginCommand;
+import com.willfp.eco.core.config.base.ConfigYml;
+import com.willfp.eco.core.config.base.LangYml;
+import com.willfp.eco.core.config.updating.ConfigHandler;
+import com.willfp.eco.core.display.Display;
+import com.willfp.eco.core.display.DisplayModule;
+import com.willfp.eco.core.events.EventManager;
+import com.willfp.eco.core.extensions.Extension;
+import com.willfp.eco.core.extensions.ExtensionLoader;
+import com.willfp.eco.core.factory.MetadataValueFactory;
+import com.willfp.eco.core.factory.NamespacedKeyFactory;
+import com.willfp.eco.core.factory.RunnableFactory;
+import com.willfp.eco.core.integrations.IntegrationLoader;
+import com.willfp.eco.core.integrations.placeholder.PlaceholderManager;
+import com.willfp.eco.core.proxy.ProxyFactory;
+import com.willfp.eco.core.scheduling.Scheduler;
+import com.willfp.eco.core.web.UpdateChecker;
+import org.apache.commons.lang.Validate;
+import org.apache.maven.artifact.versioning.DefaultArtifactVersion;
+import org.bukkit.Bukkit;
+import org.bukkit.configuration.file.FileConfiguration;
+import org.bukkit.event.Listener;
+import org.bukkit.plugin.Plugin;
+import org.bukkit.plugin.java.JavaPlugin;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Objects;
+import java.util.Set;
+import java.util.logging.Logger;
+import java.util.stream.Collectors;
+
+/**
+ * EcoPlugin is the base plugin class for eco-based plugins.
+ * <p>
+ * It functions as a replacement for {@link JavaPlugin}.
+ * <p>
+ * EcoPlugin is a lot more powerful than {@link JavaPlugin} and
+ * contains many methods to reduce boilerplate code and reduce
+ * plugin complexity.
+ * <p>
+ * It is recommended to view the source code for this class to
+ * gain a better understanding of how it works.
+ * <p>
+ * <b>IMPORTANT: When reloading a plugin, all runnables / tasks will
+ * be cancelled.</b>
+ */
+@SuppressWarnings("unused")
+public abstract class EcoPlugin extends JavaPlugin implements PluginLike {
+    /**
+     * The polymart resource ID of the plugin.
+     */
+    private final int resourceId;
+
+    /**
+     * The bStats resource ID of the plugin.
+     */
+    private final int bStatsId;
+
+    /**
+     * The package where proxy implementations are.
+     */
+    private final String proxyPackage;
+
+    /**
+     * The color of the plugin, used in messages.
+     */
+    private final String color;
+
+    /**
+     * Loaded integrations.
+     */
+    private final Set<String> loadedIntegrations = new HashSet<>();
+
+    /**
+     * The internal plugin scheduler.
+     */
+    private final Scheduler scheduler;
+
+    /**
+     * The internal plugin Event Manager.
+     */
+    private final EventManager eventManager;
+
+    /**
+     * Config.yml.
+     */
+    private final ConfigYml configYml;
+
+    /**
+     * Lang.yml.
+     */
+    private final LangYml langYml;
+
+    /**
+     * The internal factory to produce {@link org.bukkit.NamespacedKey}s.
+     */
+    private final NamespacedKeyFactory namespacedKeyFactory;
+
+    /**
+     * The internal factory to produce {@link org.bukkit.metadata.FixedMetadataValue}s.
+     */
+    private final MetadataValueFactory metadataValueFactory;
+
+    /**
+     * The internal factory to produce {@link com.willfp.eco.core.scheduling.RunnableTask}s.
+     */
+    private final RunnableFactory runnableFactory;
+
+    /**
+     * The loader for all plugin extensions.
+     *
+     * @see com.willfp.eco.core.extensions.Extension
+     */
+    private final ExtensionLoader extensionLoader;
+
+    /**
+     * The handler class for updatable classes.
+     */
+    private final ConfigHandler configHandler;
+
+    /**
+     * The display module for the plugin.
+     */
+    private DisplayModule displayModule;
+
+    /**
+     * The logger for the plugin.
+     */
+    private final Logger logger;
+
+    /**
+     * If the server is running an outdated version of the plugin.
+     */
+    private boolean outdated = false;
+
+    /**
+     * If the plugin supports extensions.
+     */
+    private final boolean supportingExtensions;
+
+    /**
+     * The proxy factory.
+     */
+    @Nullable
+    private final ProxyFactory proxyFactory;
+
+    /**
+     * Create a new plugin.
+     * <p>
+     * Will read from eco.yml (like plugin.yml) to fetch values that would otherwise be passed
+     * into the constructor. If no eco.yml is present, the plugin will load without extension
+     * support, without proxy support, with no update-checker or bStats, and with the color white.
+     */
+    protected EcoPlugin() {
+        this((PluginProps) null);
+    }
+
+    /**
+     * Create a new plugin without proxy support, polymart, or bStats.
+     *
+     * @param color The color.
+     */
+    protected EcoPlugin(@NotNull final String color) {
+        this("", color);
+    }
+
+
+    /**
+     * Create a new plugin unlinked to polymart and bStats.
+     *
+     * @param proxyPackage The package where proxy implementations are stored.
+     * @param color        The color of the plugin (used in messages, using standard formatting)
+     */
+    protected EcoPlugin(@NotNull final String proxyPackage,
+                        @NotNull final String color) {
+        this(0, 0, proxyPackage, color);
+    }
+
+    /**
+     * Create a new plugin without proxy or extension support.
+     *
+     * @param resourceId The polymart resource ID for the plugin.
+     * @param bStatsId   The bStats resource ID for the plugin.
+     * @param color      The color of the plugin (used in messages, using standard formatting)
+     */
+    protected EcoPlugin(final int resourceId,
+                        final int bStatsId,
+                        @NotNull final String color) {
+        this(resourceId, bStatsId, "", color);
+    }
+
+    /**
+     * Create a new plugin without proxy support.
+     *
+     * @param resourceId           The polymart resource ID for the plugin.
+     * @param bStatsId             The bStats resource ID for the plugin.
+     * @param color                The color of the plugin (used in messages, using standard formatting)
+     * @param supportingExtensions If the plugin supports extensions.
+     */
+    protected EcoPlugin(final int resourceId,
+                        final int bStatsId,
+                        @NotNull final String color,
+                        final boolean supportingExtensions) {
+        this(resourceId, bStatsId, "", color, supportingExtensions);
+    }
+
+    /**
+     * Create a new plugin without extension support.
+     *
+     * @param resourceId   The polymart resource ID for the plugin.
+     * @param bStatsId     The bStats resource ID for the plugin.
+     * @param proxyPackage The package where proxy implementations are stored.
+     * @param color        The color of the plugin (used in messages, using standard formatting)
+     */
+    protected EcoPlugin(final int resourceId,
+                        final int bStatsId,
+                        @NotNull final String proxyPackage,
+                        @NotNull final String color) {
+        this(resourceId, bStatsId, proxyPackage, color, false);
+    }
+
+    /**
+     * Create a new plugin.
+     *
+     * @param resourceId           The polymart resource ID for the plugin.
+     * @param bStatsId             The bStats resource ID for the plugin.
+     * @param proxyPackage         The package where proxy implementations are stored.
+     * @param color                The color of the plugin (used in messages, using standard formatting)
+     * @param supportingExtensions If the plugin supports extensions.
+     */
+    protected EcoPlugin(final int resourceId,
+                        final int bStatsId,
+                        @NotNull final String proxyPackage,
+                        @NotNull final String color,
+                        final boolean supportingExtensions) {
+        this(
+                PluginProps.createSimple(
+                        resourceId,
+                        bStatsId,
+                        proxyPackage,
+                        color,
+                        supportingExtensions
+                )
+        );
+    }
+
+    /**
+     * Create a new plugin.
+     *
+     * @param pluginProps The props. If left null, it will read from eco.yml.
+     */
+    protected EcoPlugin(@Nullable final PluginProps pluginProps) {
+        /*
+        The handler must be initialized before any plugin's constructors
+        are called, as the constructors call Eco#getHandler().
+
+        To fix this, EcoSpigotPlugin an abstract class and the 'actual'
+        plugin class is EcoHandler - that way I can create the handler
+        before any plugins are loaded while still having a separation between
+        the plugin class and the handler class (for code clarity).
+
+        I don't really like the fact that the handler class *is* the
+        spigot plugin, but it is what it is.
+
+        There is probably a better way of doing it - maybe with
+        some sort of HandlerCreator interface in order to still have
+        a standalone handler class, but then there would be an interface
+        left in the API that doesn't really help anything.
+
+        The other alternative would be to use reflection to get a 'createHandler'
+        method that only exists in EcoSpigotPlugin - but that feels filthy,
+        and I'd rather only use reflection where necessary.
+        */
+
+        if (Eco.getHandler() == null && this instanceof Handler) {
+            /*
+            This code is only ever called by EcoSpigotPlugin (EcoHandler)
+            as it's the first plugin to load, and it is a handler.
+
+            Any other plugins will never call this code as the handler
+            will have already been initialized.
+             */
+
+            Eco.setHandler((Handler) this);
+        }
+
+        assert Eco.getHandler() != null;
+
+        PluginProps generatedProps = Eco.getHandler().getProps(pluginProps, this.getClass());
+        generatedProps.validate();
+        PluginProps props = this.mutateProps(generatedProps);
+        props.validate();
+
+        this.resourceId = props.getResourceId();
+        this.bStatsId = props.getBStatsId();
+        this.proxyPackage = props.getProxyPackage();
+        this.color = props.getColor();
+        this.supportingExtensions = props.isSupportingExtensions();
+
+        this.scheduler = Eco.getHandler().createScheduler(this);
+        this.eventManager = Eco.getHandler().createEventManager(this);
+        this.namespacedKeyFactory = Eco.getHandler().createNamespacedKeyFactory(this);
+        this.metadataValueFactory = Eco.getHandler().createMetadataValueFactory(this);
+        this.runnableFactory = Eco.getHandler().createRunnableFactory(this);
+        this.extensionLoader = Eco.getHandler().createExtensionLoader(this);
+        this.configHandler = Eco.getHandler().createConfigHandler(this);
+        this.logger = Eco.getHandler().createLogger(this);
+        this.proxyFactory = this.proxyPackage.equalsIgnoreCase("") ? null : Eco.getHandler().createProxyFactory(this);
+
+        this.langYml = this.createLangYml();
+        this.configYml = this.createConfigYml();
+
+        Eco.getHandler().addNewPlugin(this);
+
+        /*
+        The minimum eco version check was moved here because it's very common
+        to add a lot of code in the constructor of plugins; meaning that the plugin
+        can throw errors without it being obvious to the user that the reason is that
+        they have an outdated version of eco installed.
+         */
+
+        DefaultArtifactVersion runningVersion = new DefaultArtifactVersion(Eco.getHandler().getEcoPlugin().getDescription().getVersion());
+        DefaultArtifactVersion requiredVersion = new DefaultArtifactVersion(this.getMinimumEcoVersion());
+        if (!(runningVersion.compareTo(requiredVersion) > 0 || runningVersion.equals(requiredVersion))) {
+            this.getLogger().severe("You are running an outdated version of eco!");
+            this.getLogger().severe("You must be on at least" + this.getMinimumEcoVersion());
+            this.getLogger().severe("Download the newest version here:");
+            this.getLogger().severe("https://polymart.org/download/773/recent/JSpprMspkuyecf5y1wQ2Jn8OoLQSQ_IW");
+            Bukkit.getPluginManager().disablePlugin(this);
+        }
+    }
+
+    /**
+     * Default code to be executed on plugin enable.
+     */
+    @Override
+    public final void onEnable() {
+        super.onEnable();
+
+        this.getLogger().info("");
+        this.getLogger().info("Loading " + this.getColor() + this.getName());
+
+        if (this.getResourceId() != 0) {
+            new UpdateChecker(this).getVersion(version -> {
+                DefaultArtifactVersion currentVersion = new DefaultArtifactVersion(this.getDescription().getVersion());
+                DefaultArtifactVersion mostRecentVersion = new DefaultArtifactVersion(version);
+                if (!(currentVersion.compareTo(mostRecentVersion) > 0 || currentVersion.equals(mostRecentVersion))) {
+                    this.outdated = true;
+                    this.getLogger().warning("&c" + this.getName() + " is out of date! (Version " + this.getDescription().getVersion() + ")");
+                    this.getLogger().warning("&cThe newest version is &f" + version);
+                    this.getLogger().warning("&cDownload the new version!");
+                }
+            });
+        }
+
+        if (this.getBStatsId() != 0) {
+            Eco.getHandler().registerBStats(this);
+        }
+
+        Set<String> enabledPlugins = Arrays.stream(Bukkit.getPluginManager().getPlugins())
+                .map(Plugin::getName)
+                .map(String::toLowerCase)
+                .collect(Collectors.toSet());
+
+        if (enabledPlugins.contains("PlaceholderAPI".toLowerCase())) {
+            this.loadedIntegrations.add("PlaceholderAPI");
+            PlaceholderManager.addIntegration(Eco.getHandler().createPAPIIntegration(this));
+        }
+
+        this.loadIntegrationLoaders().forEach((integrationLoader -> {
+            if (enabledPlugins.contains(integrationLoader.getPluginName().toLowerCase())) {
+                this.loadedIntegrations.add(integrationLoader.getPluginName());
+                integrationLoader.load();
+            }
+        }));
+
+        this.getLogger().info("Loaded integrations: " + String.join(", ", this.getLoadedIntegrations()));
+
+        Prerequisite.update();
+
+        this.loadPacketAdapters().forEach(abstractPacketAdapter -> {
+            if (!abstractPacketAdapter.isPostLoad()) {
+                abstractPacketAdapter.register();
+            }
+        });
+
+        this.loadListeners().forEach(listener -> this.getEventManager().registerListener(listener));
+
+        this.loadPluginCommands().forEach(PluginCommand::register);
+
+        this.getScheduler().runLater(this::afterLoad, 1);
+
+        if (this.isSupportingExtensions()) {
+            this.getExtensionLoader().loadExtensions();
+
+            if (this.getExtensionLoader().getLoadedExtensions().isEmpty()) {
+                this.getLogger().info("&cNo extensions found");
+            } else {
+                this.getLogger().info("Extensions Loaded:");
+                this.getExtensionLoader().getLoadedExtensions().forEach(extension -> this.getLogger().info("- " + extension.getName() + " v" + extension.getVersion()));
+            }
+        }
+
+        this.handleEnable();
+
+        this.getLogger().info("");
+    }
+
+    /**
+     * Default code to be executed on plugin disable.
+     */
+    @Override
+    public final void onDisable() {
+        super.onDisable();
+
+        this.getEventManager().unregisterAllListeners();
+        this.getScheduler().cancelAll();
+
+        this.handleDisable();
+
+        if (this.isSupportingExtensions()) {
+            this.getExtensionLoader().unloadExtensions();
+        }
+
+        this.getLogger().info("Cleaning up...");
+        Eco.getHandler().getCleaner().clean(this);
+    }
+
+    /**
+     * Default code to be executed on plugin load.
+     */
+    @Override
+    public final void onLoad() {
+        super.onLoad();
+
+        this.handleLoad();
+    }
+
+    /**
+     * Default code to be executed after the server is up.
+     */
+    public final void afterLoad() {
+        this.displayModule = createDisplayModule();
+
+        if (this.getDisplayModule() != null) {
+            Display.registerDisplayModule(this.getDisplayModule());
+        }
+
+        this.loadPacketAdapters().forEach(abstractPacketAdapter -> {
+            if (abstractPacketAdapter.isPostLoad()) {
+                abstractPacketAdapter.register();
+            }
+        });
+
+        if (!Prerequisite.HAS_PAPER.isMet()) {
+            this.getLogger().severe("");
+            this.getLogger().severe("----------------------------");
+            this.getLogger().severe("");
+            this.getLogger().severe("You don't seem to be running paper!");
+            this.getLogger().severe("Paper is strongly recommended for all servers,");
+            this.getLogger().severe("and some things may not function properly without it");
+            this.getLogger().severe("Download Paper from &fhttps://papermc.io");
+            this.getLogger().severe("");
+            this.getLogger().severe("----------------------------");
+            this.getLogger().severe("");
+        }
+
+        this.handleAfterLoad();
+
+        this.reload();
+
+        for (Extension extension : this.getExtensionLoader().getLoadedExtensions()) {
+            extension.handleAfterLoad();
+        }
+
+        this.getLogger().info("Loaded " + this.color + this.getName());
+    }
+
+    /**
+     * Reload the plugin.
+     */
+    public final void reload() {
+        this.getConfigHandler().updateConfigs();
+
+        this.getConfigHandler().callUpdate();
+        this.getConfigHandler().callUpdate(); // Call twice to fix issues
+        this.getScheduler().cancelAll();
+
+        this.handleReload();
+
+        for (Extension extension : this.extensionLoader.getLoadedExtensions()) {
+            extension.handleReload();
+        }
+    }
+
+    /**
+     * Reload the plugin and return the time taken to reload.
+     *
+     * @return The time.
+     */
+    public final long reloadWithTime() {
+        long startTime = System.currentTimeMillis();
+
+        this.reload();
+
+        return System.currentTimeMillis() - startTime;
+    }
+
+    /**
+     * The plugin-specific code to be executed on enable.
+     * <p>
+     * Override when needed.
+     */
+    protected void handleEnable() {
+
+    }
+
+    /**
+     * The plugin-specific code to be executed on disable.
+     * <p>
+     * Override when needed.
+     */
+    protected void handleDisable() {
+
+    }
+
+    /**
+     * The plugin-specific code to be executed on load.
+     * <p>
+     * This is executed before enabling.
+     * <p>
+     * Override when needed.
+     */
+    protected void handleLoad() {
+
+    }
+
+    /**
+     * The plugin-specific code to be executed on reload.
+     * <p>
+     * Override when needed.
+     */
+    protected void handleReload() {
+
+    }
+
+    /**
+     * The plugin-specific code to be executed after the server is up.
+     * <p>
+     * Override when needed.
+     */
+    protected void handleAfterLoad() {
+
+    }
+
+    /**
+     * Mutate the plugin props.
+     * <p>
+     * Useful for eco-based plugin libraries to enforce certain properties, such as
+     * forcing extensions to be enabled.
+     * <p>
+     * Props are validated both before and after calling this method.
+     *
+     * @param props The props.
+     * @return The mutated props.
+     */
+    protected PluginProps mutateProps(@NotNull final PluginProps props) {
+        return props;
+    }
+
+    /**
+     * The plugin-specific integrations to be tested and loaded.
+     *
+     * @return A list of integrations.
+     */
+    protected List<IntegrationLoader> loadIntegrationLoaders() {
+        return new ArrayList<>();
+    }
+
+    /**
+     * The commands to be registered.
+     *
+     * @return A list of commands.
+     */
+    protected List<PluginCommand> loadPluginCommands() {
+        return new ArrayList<>();
+    }
+
+    /**
+     * ProtocolLib packet adapters to be registered.
+     * <p>
+     * If the plugin does not require ProtocolLib this can be left empty.
+     *
+     * @return A list of packet adapters.
+     */
+    protected List<AbstractPacketAdapter> loadPacketAdapters() {
+        return new ArrayList<>();
+    }
+
+    /**
+     * All listeners to be registered.
+     *
+     * @return A list of all listeners.
+     */
+    protected abstract List<Listener> loadListeners();
+
+    /**
+     * Useful for custom LangYml implementations.
+     * <p>
+     * Override if needed.
+     *
+     * @return lang.yml.
+     */
+    protected LangYml createLangYml() {
+        return new LangYml(this);
+    }
+
+    /**
+     * Useful for custom ConfigYml implementations.
+     * <p>
+     * Override if needed.
+     *
+     * @return config.yml.
+     */
+    protected ConfigYml createConfigYml() {
+        return new ConfigYml(this);
+    }
+
+    /**
+     * Create the display module for the plugin.
+     *
+     * @return The display module, or null.
+     */
+    @Nullable
+    protected DisplayModule createDisplayModule() {
+        Validate.isTrue(
+                this.getDisplayModule() == null,
+                "Display module exists!"
+        );
+
+        return null;
+    }
+
+    /**
+     * Get the minimum version of eco to use the plugin.
+     *
+     * @return The version.
+     */
+    public String getMinimumEcoVersion() {
+        return "6.0.0";
+    }
+
+    /**
+     * Get the plugin's logger.
+     *
+     * @return The logger.
+     */
+    @NotNull
+    @Override
+    public Logger getLogger() {
+        return logger;
+    }
+
+    /**
+     * Get a proxy.
+     *
+     * @param proxyClass The proxy class.
+     * @param <T>        The proxy type.
+     * @return The proxy.
+     */
+    public final <T> T getProxy(@NotNull final Class<T> proxyClass) {
+        Validate.notNull(proxyFactory, "Plugin does not support proxies!");
+
+        return proxyFactory.getProxy(proxyClass);
+    }
+
+    /**
+     * Get unwrapped config.
+     * Does not use eco config system, don't use.
+     *
+     * @return The bukkit config.
+     * @deprecated Use getConfigYml() instead.
+     */
+    @NotNull
+    @Override
+    @Deprecated
+    public final FileConfiguration getConfig() {
+        this.getLogger().warning("Call to default config method in eco plugin!");
+
+        return Objects.requireNonNull(this.getConfigYml().getBukkitHandle());
+    }
+
+    /**
+     * Does not use eco config system, don't use.
+     *
+     * @deprecated Use eco config system.
+     */
+    @Override
+    @Deprecated
+    public final void saveConfig() {
+        this.getLogger().warning("Call to default config method in eco plugin!");
+
+        super.saveConfig();
+    }
+
+    /**
+     * Does not use eco config system, don't use.
+     *
+     * @deprecated Use eco config system.
+     */
+    @Override
+    @Deprecated
+    public final void saveDefaultConfig() {
+        this.getLogger().warning("Call to default config method in eco plugin!");
+
+        super.saveDefaultConfig();
+    }
+
+    /**
+     * Does not use eco config system, don't use.
+     *
+     * @deprecated Use eco config system.
+     */
+    @Override
+    @Deprecated
+    public final void reloadConfig() {
+        this.getLogger().warning("Call to default config method in eco plugin!");
+
+        super.reloadConfig();
+    }
+
+    /**
+     * Get an EcoPlugin by name.
+     *
+     * @param pluginName The name.
+     * @return The plugin.
+     */
+    public static EcoPlugin getPlugin(@NotNull final String pluginName) {
+        return Eco.getHandler().getPluginByName(pluginName);
+    }
+
+    /**
+     * Get all EcoPlugin names.
+     *
+     * @return The set of names.
+     */
+    public static Set<String> getPluginNames() {
+        return new HashSet<>(Eco.getHandler().getLoadedPlugins());
+    }
+
+    /**
+     * Get the polymart resource ID.
+     *
+     * @return The resource ID.
+     */
+    public int getResourceId() {
+        return this.resourceId;
+    }
+
+    /**
+     * Get the bStats ID.
+     *
+     * @return The ID.
+     */
+    public int getBStatsId() {
+        return this.bStatsId;
+    }
+
+    /**
+     * Get the proxy package.
+     *
+     * @return The package where proxies are contained.
+     */
+    public String getProxyPackage() {
+        return this.proxyPackage;
+    }
+
+    /**
+     * Get the plugin color (uses legacy formatting).
+     *
+     * @return The color.
+     */
+    public String getColor() {
+        return this.color;
+    }
+
+    /**
+     * Get all loaded integration names.
+     *
+     * @return The integrations.
+     */
+    public Set<String> getLoadedIntegrations() {
+        return this.loadedIntegrations;
+    }
+
+    /**
+     * Get the scheduler.
+     *
+     * @return The scheduler.
+     */
+    public Scheduler getScheduler() {
+        return this.scheduler;
+    }
+
+    /**
+     * Get the event manager.
+     *
+     * @return The event manager.
+     */
+    public EventManager getEventManager() {
+        return this.eventManager;
+    }
+
+    /**
+     * Get config.yml.
+     *
+     * @return config.yml.
+     */
+    public ConfigYml getConfigYml() {
+        return this.configYml;
+    }
+
+    /**
+     * Get lang.yml.
+     *
+     * @return lang.yml.
+     */
+    public LangYml getLangYml() {
+        return this.langYml;
+    }
+
+    /**
+     * Get the NamespacedKey factory.
+     *
+     * @return The factory.
+     */
+    public NamespacedKeyFactory getNamespacedKeyFactory() {
+        return this.namespacedKeyFactory;
+    }
+
+    /**
+     * Get the metadata value factory.
+     *
+     * @return The factory.
+     */
+    public MetadataValueFactory getMetadataValueFactory() {
+        return this.metadataValueFactory;
+    }
+
+    /**
+     * Get the runnable factory.
+     *
+     * @return The runnable factory.
+     */
+    public RunnableFactory getRunnableFactory() {
+        return this.runnableFactory;
+    }
+
+    /**
+     * Get the extension loader.
+     *
+     * @return The extension loader.
+     */
+    public ExtensionLoader getExtensionLoader() {
+        return this.extensionLoader;
+    }
+
+    /**
+     * Get the config handler.
+     *
+     * @return The config handler.
+     */
+    public ConfigHandler getConfigHandler() {
+        return this.configHandler;
+    }
+
+    /**
+     * Get the plugin's display module.
+     *
+     * @return The display module.
+     */
+    @Nullable
+    public DisplayModule getDisplayModule() {
+        return this.displayModule;
+    }
+
+    /**
+     * Get if the plugin is outdated.
+     *
+     * @return If outdated.
+     */
+    public boolean isOutdated() {
+        return this.outdated;
+    }
+
+    /**
+     * Get if the plugin supports extensions.
+     *
+     * @return If extensions are supported.
+     */
+    public boolean isSupportingExtensions() {
+        return this.supportingExtensions;
+    }
+
+    /**
+     * Get the proxy factory.
+     *
+     * @return The proxy factory.
+     */
+    @Nullable
+    public ProxyFactory getProxyFactory() {
+        return this.proxyFactory;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/Handler.java

@@ -0,0 +1,265 @@
+package com.willfp.eco.core;
+
+import com.willfp.eco.core.config.updating.ConfigHandler;
+import com.willfp.eco.core.config.wrapper.ConfigFactory;
+import com.willfp.eco.core.data.ProfileHandler;
+import com.willfp.eco.core.data.keys.KeyRegistry;
+import com.willfp.eco.core.drops.DropQueueFactory;
+import com.willfp.eco.core.events.EventManager;
+import com.willfp.eco.core.extensions.ExtensionLoader;
+import com.willfp.eco.core.factory.MetadataValueFactory;
+import com.willfp.eco.core.factory.NamespacedKeyFactory;
+import com.willfp.eco.core.factory.RunnableFactory;
+import com.willfp.eco.core.fast.FastItemStack;
+import com.willfp.eco.core.gui.GUIFactory;
+import com.willfp.eco.core.integrations.placeholder.PlaceholderIntegration;
+import com.willfp.eco.core.proxy.Cleaner;
+import com.willfp.eco.core.proxy.ProxyFactory;
+import com.willfp.eco.core.scheduling.Scheduler;
+import net.kyori.adventure.platform.bukkit.BukkitAudiences;
+import org.bukkit.Location;
+import org.bukkit.NamespacedKey;
+import org.bukkit.entity.Entity;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.List;
+import java.util.logging.Logger;
+
+/**
+ * @see Eco#getHandler()
+ */
+@ApiStatus.Internal
+@SuppressWarnings("removal")
+public interface Handler {
+    /**
+     * Create a scheduler.
+     *
+     * @param plugin The plugin.
+     * @return The scheduler.
+     */
+    @NotNull
+    Scheduler createScheduler(@NotNull EcoPlugin plugin);
+
+    /**
+     * Create an event manager.
+     *
+     * @param plugin The plugin.
+     * @return The event manager.
+     */
+    @NotNull
+    EventManager createEventManager(@NotNull EcoPlugin plugin);
+
+    /**
+     * Create a NamespacedKey factory.
+     *
+     * @param plugin The plugin.
+     * @return The factory.
+     */
+    @NotNull
+    NamespacedKeyFactory createNamespacedKeyFactory(@NotNull EcoPlugin plugin);
+
+    /**
+     * Create a MetadataValue factory.
+     *
+     * @param plugin The plugin.
+     * @return The factory.
+     */
+    @NotNull
+    MetadataValueFactory createMetadataValueFactory(@NotNull EcoPlugin plugin);
+
+    /**
+     * Create a Runnable factory.
+     *
+     * @param plugin The plugin.
+     * @return The factory.
+     */
+    @NotNull
+    RunnableFactory createRunnableFactory(@NotNull EcoPlugin plugin);
+
+    /**
+     * Create an ExtensionLoader.
+     *
+     * @param plugin The plugin.
+     * @return The factory.
+     */
+    @NotNull
+    ExtensionLoader createExtensionLoader(@NotNull EcoPlugin plugin);
+
+    /**
+     * Create a config handler.
+     *
+     * @param plugin The plugin.
+     * @return The handler.
+     */
+    @NotNull
+    ConfigHandler createConfigHandler(@NotNull EcoPlugin plugin);
+
+    /**
+     * Create a logger.
+     *
+     * @param plugin The plugin.
+     * @return The logger.
+     */
+    @NotNull
+    Logger createLogger(@NotNull EcoPlugin plugin);
+
+    /**
+     * Create a PAPI integration.
+     *
+     * @param plugin The plugin.
+     * @return The integration.
+     */
+    @NotNull
+    PlaceholderIntegration createPAPIIntegration(@NotNull EcoPlugin plugin);
+
+    /**
+     * Create a proxy factory.
+     *
+     * @param plugin The plugin.
+     * @return The factory.
+     */
+    @NotNull
+    ProxyFactory createProxyFactory(@NotNull EcoPlugin plugin);
+
+    /**
+     * Get eco Spigot plugin.
+     *
+     * @return The plugin.
+     */
+    @NotNull
+    EcoPlugin getEcoPlugin();
+
+    /**
+     * Get config factory.
+     *
+     * @return The factory.
+     */
+    @NotNull
+    ConfigFactory getConfigFactory();
+
+    /**
+     * Get drop queue factory.
+     *
+     * @return The factory.
+     */
+    @NotNull
+    DropQueueFactory getDropQueueFactory();
+
+    /**
+     * Get GUI factory.
+     *
+     * @return The factory.
+     */
+    @NotNull
+    GUIFactory getGUIFactory();
+
+    /**
+     * Get cleaner.
+     *
+     * @return The cleaner.
+     */
+    @NotNull
+    Cleaner getCleaner();
+
+    /**
+     * Add new plugin.
+     *
+     * @param plugin The plugin.
+     */
+    void addNewPlugin(@NotNull EcoPlugin plugin);
+
+    /**
+     * Get plugin by name.
+     *
+     * @param name The name.
+     * @return The plugin.
+     */
+    @Nullable
+    EcoPlugin getPluginByName(@NotNull String name);
+
+    /**
+     * Get all loaded eco plugins.
+     *
+     * @return A list of plugin names in lowercase.
+     */
+    @NotNull
+    List<String> getLoadedPlugins();
+
+    /**
+     * Create a FastItemStack.
+     *
+     * @param itemStack The base ItemStack.
+     * @return The FastItemStack.
+     */
+    @NotNull
+    FastItemStack createFastItemStack(@NotNull ItemStack itemStack);
+
+    /**
+     * Register bStats metrics.
+     *
+     * @param plugin The plugin.
+     */
+    void registerBStats(@NotNull EcoPlugin plugin);
+
+    /**
+     * Get Adventure audiences.
+     *
+     * @return The audiences.
+     */
+    @Nullable
+    BukkitAudiences getAdventure();
+
+    /**
+     * Get the key registry.
+     *
+     * @return The registry.
+     */
+    @NotNull
+    KeyRegistry getKeyRegistry();
+
+    /**
+     * Get the PlayerProfile handler.
+     *
+     * @return The handler.
+     */
+    @NotNull
+    ProfileHandler getProfileHandler();
+
+    /**
+     * Create dummy entity - never spawned, exists purely in code.
+     *
+     * @param location The location.
+     * @return The entity.
+     */
+    @NotNull
+    Entity createDummyEntity(@NotNull Location location);
+
+    /**
+     * Create a {@link NamespacedKey} quickly
+     * <p>
+     * Bypasses the constructor, allowing for the creation of invalid keys,
+     * therefore this is considered unsafe and should only be called after
+     * the key has been confirmed to be valid.
+     *
+     * @param namespace The namespace.
+     * @param key       The key.
+     * @return The key.
+     */
+    @NotNull
+    NamespacedKey createNamespacedKey(@NotNull String namespace,
+                                      @NotNull String key);
+
+    /**
+     * Return or get props for a plugin.
+     *
+     * @param existing The existing constructor props.
+     * @param plugin   The plugin.
+     * @return The props.
+     */
+    @NotNull
+    PluginProps getProps(@Nullable PluginProps existing,
+                         @NotNull Class<? extends EcoPlugin> plugin);
+}

eco-api/src/main/java/com/willfp/eco/core/PluginDependent.java

@@ -0,0 +1,42 @@
+package com.willfp.eco.core;
+
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Quick DI class to manage passing eco plugins.
+ * <p>
+ * Basically just a quick bit of laziness if you can't be bothered to add a private field
+ * and a protected getter, don't use this in kotlin as you can just specify
+ * {@code
+ * private val plugin: EcoPlugin
+ * }
+ * in the constructor.
+ *
+ * @param <T> The eco plugin type.
+ */
+public abstract class PluginDependent<T extends EcoPlugin> {
+    /**
+     * The {@link EcoPlugin} that is stored.
+     */
+    @NotNull
+    private final T plugin;
+
+    /**
+     * Pass an {@link EcoPlugin} in order to interface with it.
+     *
+     * @param plugin The plugin to manage.
+     */
+    protected PluginDependent(@NotNull final T plugin) {
+        this.plugin = plugin;
+    }
+
+    /**
+     * Get the plugin.
+     *
+     * @return The plugin.
+     */
+    @NotNull
+    protected T getPlugin() {
+        return this.plugin;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/PluginLike.java

@@ -0,0 +1,37 @@
+package com.willfp.eco.core;
+
+import com.willfp.eco.core.config.updating.ConfigHandler;
+
+import java.io.File;
+import java.util.logging.Logger;
+
+/**
+ * Represents any class that acts like a plugin, for example {@link EcoPlugin}
+ * or {@link com.willfp.eco.core.extensions.Extension}. This exists to create
+ * things such as extension base configs rather than needing to pass an instance
+ * of the owning plugin.
+ */
+public interface PluginLike {
+    /**
+     * Get the data folder of the object.
+     * <p>
+     * Returns the plugin data folder for a plugin, or the extension's parent plugin's folder
+     *
+     * @return The data folder.
+     */
+    File getDataFolder();
+
+    /**
+     * Get the handler class for updatable classes.
+     *
+     * @return The config handler.
+     */
+    ConfigHandler getConfigHandler();
+
+    /**
+     * Get the logger.
+     *
+     * @return The logger.
+     */
+    Logger getLogger();
+}

eco-api/src/main/java/com/willfp/eco/core/PluginProps.java

@@ -0,0 +1,275 @@
+package com.willfp.eco.core;
+
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Plugin props are the arguments related to the plugin that are required on start-up.
+ * <p>
+ * This class is complex in how it works intentionally. This is done so that fields can be
+ * added to the props without breaking API backwards compatibility. Thus, there is no public
+ * constructor and no way to instantiate props without creating a parser.
+ */
+public final class PluginProps {
+    /**
+     * All registered parsers.
+     */
+    private static final Map<Class<?>, PropsParser<?>> REGISTERED_PARSERS = new HashMap<>();
+
+    /**
+     * The polymart resource ID.
+     */
+    @Nullable
+    private Integer resourceId;
+
+    /**
+     * The bStats ID.
+     */
+    @Nullable
+    private Integer bStatsId;
+
+    /**
+     * The proxy package.
+     */
+    @Nullable
+    private String proxyPackage;
+
+    /**
+     * The color.
+     */
+    @Nullable
+    private String color;
+
+    /**
+     * If extensions are supported.
+     */
+    @Nullable
+    private Boolean supportingExtensions;
+
+    /**
+     * Create new blank props.
+     */
+    private PluginProps() {
+
+    }
+
+    /**
+     * Get resource ID.
+     *
+     * @return The resource ID.
+     */
+    public int getResourceId() {
+        assert resourceId != null;
+        return resourceId;
+    }
+
+    /**
+     * Set resource ID.
+     *
+     * @param resourceId The resource ID.
+     */
+    public void setResourceId(final int resourceId) {
+        this.resourceId = resourceId;
+    }
+
+    /**
+     * Get bStats ID.
+     *
+     * @return The bStats ID.
+     */
+    public int getBStatsId() {
+        assert bStatsId != null;
+        return bStatsId;
+    }
+
+    /**
+     * Set bStats ID.
+     *
+     * @param bStatsId The bStats ID.
+     */
+    public void setBStatsId(final int bStatsId) {
+        this.bStatsId = bStatsId;
+    }
+
+    /**
+     * Get the proxy package.
+     *
+     * @return The package.
+     */
+    @NotNull
+    public String getProxyPackage() {
+        assert proxyPackage != null;
+        return proxyPackage;
+    }
+
+    /**
+     * Set the proxy package.
+     *
+     * @param proxyPackage The proxy package.
+     */
+    public void setProxyPackage(@NotNull final String proxyPackage) {
+        this.proxyPackage = proxyPackage;
+    }
+
+    /**
+     * Get color.
+     *
+     * @return The color.
+     */
+    @NotNull
+    public String getColor() {
+        assert color != null;
+        return color;
+    }
+
+    /**
+     * Set the color.
+     *
+     * @param color The color.
+     */
+    public void setColor(@NotNull final String color) {
+        this.color = color;
+    }
+
+    /**
+     * Get if extensions are supported.
+     *
+     * @return If supported.
+     */
+    public boolean isSupportingExtensions() {
+        assert supportingExtensions != null;
+        return supportingExtensions;
+    }
+
+    /**
+     * Set if extensions are supported.
+     *
+     * @param supportingExtensions If supported.
+     */
+    public void setSupportingExtensions(final boolean supportingExtensions) {
+        this.supportingExtensions = supportingExtensions;
+    }
+
+    /**
+     * Ensure that all required props have been set.
+     */
+    public void validate() {
+        if (
+                supportingExtensions == null
+                        || proxyPackage == null
+                        || color == null
+                        || bStatsId == null
+                        || resourceId == null
+        ) {
+            throw new IllegalStateException("Missing required props!");
+        }
+    }
+
+    /**
+     * Parse props from source.
+     *
+     * @param source      The source.
+     * @param sourceClass The source class.
+     * @param <T>         The source type.
+     * @return The props.
+     */
+    public static <T> PluginProps parse(@NotNull final T source,
+                                        @NotNull final Class<? extends T> sourceClass) {
+        for (Map.Entry<Class<?>, PropsParser<?>> entry : REGISTERED_PARSERS.entrySet()) {
+            Class<?> clazz = entry.getKey();
+
+            if (clazz.equals(sourceClass)) {
+                @SuppressWarnings("unchecked")
+                PropsParser<T> parser = (PropsParser<T>) entry.getValue();
+                return parser.parseFrom(source);
+            }
+        }
+
+        throw new IllegalArgumentException("No parser exists for class " + sourceClass);
+    }
+
+    /**
+     * Register a parser for a type.
+     *
+     * @param clazz  The class.
+     * @param parser The parser.
+     * @param <T>    The source type.
+     */
+    public static <T> void registerParser(@NotNull final Class<T> clazz,
+                                          @NotNull final PropsParser<T> parser) {
+        REGISTERED_PARSERS.put(clazz, parser);
+    }
+
+    /**
+     * Get if there is a registered parser for a class.
+     *
+     * @param clazz The class.
+     * @return If there is a parser registered.
+     */
+    public static boolean hasParserFor(@NotNull final Class<?> clazz) {
+        for (Class<?> test : REGISTERED_PARSERS.keySet()) {
+            if (test.equals(clazz)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    /**
+     * Create new props from known values.
+     *
+     * Marked as internal as this method will break whenever the properties themselves
+     * are updated (e.g. if a new property is added) - so to prevent any potential
+     * backwards-compatibility bugs, this method cannot be invoked outside eco itself.
+     *
+     * @param resourceId         The ID of the plugin on polymart.
+     * @param bStatsId           The ID of the plugin on bStats.
+     * @param proxyPackage       The package where proxies can be found.
+     * @param color              The primary color of the plugin.
+     * @param supportsExtensions If the plugin should attempt to look for extensions.
+     * @return The props.
+     */
+    @ApiStatus.Internal
+    static PluginProps createSimple(final int resourceId,
+                                    final int bStatsId,
+                                    @NotNull final String proxyPackage,
+                                    @NotNull final String color,
+                                    final boolean supportsExtensions) {
+        PluginProps props = new PluginProps();
+        props.setResourceId(resourceId);
+        props.setBStatsId(bStatsId);
+        props.setProxyPackage(proxyPackage);
+        props.setColor(color);
+        props.setSupportingExtensions(supportsExtensions);
+        return props;
+    }
+
+    /**
+     * Parse arguments into props for a plugin.
+     *
+     * @param <T> The type of source.
+     */
+    public interface PropsParser<T> {
+        /**
+         * Parse props from a given source.
+         *
+         * @param source The source.
+         * @return The props.
+         */
+        PluginProps parseFrom(@NotNull T source);
+
+        /**
+         * Get a new, blank props instance.
+         *
+         * @return Blank props.
+         */
+        default PluginProps getBlankProps() {
+            return new PluginProps();
+        }
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/Prerequisite.java

@@ -1,8 +1,8 @@
-package com.willfp.eco.util.optional;
+package com.willfp.eco.core;
 
+import com.willfp.eco.core.integrations.economy.EconomyManager;
+import com.willfp.eco.core.proxy.ProxyConstants;
 import com.willfp.eco.util.ClassUtils;
-import lombok.Getter;
-import org.bukkit.Bukkit;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.ArrayList;
@@ -10,20 +10,18 @@ import java.util.Arrays;
 import java.util.List;
 import java.util.function.Supplier;
 
+/**
+ * A prerequisite is a requirement for something.
+ * <p>
+ * For example, you can require the server to have paper or be a specific version,
+ * or have some other dependency.
+ */
 public class Prerequisite {
     /**
      * All existing prerequisites are registered on creation.
      */
     private static final List<Prerequisite> VALUES = new ArrayList<>();
 
-    /**
-     * Requires the server to be running minecraft version 1.16 or higher.
-     */
-    public static final Prerequisite MINIMUM_1_16 = new Prerequisite(
-            () -> !Bukkit.getServer().getClass().getPackage().getName().split("\\.")[3].contains("15"),
-            "Requires minimum server version of 1.16"
-    );
-
     /**
      * Requires the server to be running an implementation of paper.
      */
@@ -32,10 +30,55 @@ public class Prerequisite {
             "Requires server to be running paper (or a fork)"
     );
 
+    /**
+     * Requires the server to have vault installed.
+     *
+     * @deprecated Use {@link EconomyManager#hasRegistrations()} instead.
+     */
+    @Deprecated
+    public static final Prerequisite HAS_VAULT = new Prerequisite(
+            () -> ClassUtils.exists("net.milkbowl.vault.economy.Economy"),
+            "Requires server to have vault"
+    );
+
+    /**
+     * Requires the server to be running 1.18.
+     */
+    public static final Prerequisite HAS_1_18 = new Prerequisite(
+            () -> ProxyConstants.NMS_VERSION.contains("18"),
+            "Requires server to be running 1.18+"
+    );
+
+    /**
+     * Requires the server to be running 1.17.
+     *
+     * @deprecated eco no longer supports versions before 1.17.
+     */
+    @Deprecated(since = "6.25.2")
+    public static final Prerequisite HAS_1_17 = new Prerequisite(
+            () -> ProxyConstants.NMS_VERSION.contains("17") || HAS_1_18.isMet(),
+            "Requires server to be running 1.17+"
+    );
+
+    /**
+     * Requires the server to be running an implementation of BungeeCord.
+     */
+    public static final Prerequisite HAS_BUNGEECORD = new Prerequisite(
+            () -> ClassUtils.exists("net.md_5.bungee.api.event.ServerConnectedEvent"),
+            "Requires server to be running BungeeCord (or a fork)"
+    );
+
+    /**
+     * Requires the server to be running an implementation of Velocity.
+     */
+    public static final Prerequisite HAS_VELOCITY = new Prerequisite(
+            () -> ClassUtils.exists("com.velocitypowered.api.event.player.ServerConnectedEvent"),
+            "Requires server to be running Velocity (or a fork)"
+    );
+
     /**
      * If the necessary prerequisite condition has been met.
      */
-    @Getter
     private boolean isMet;
 
     /**
@@ -46,7 +89,6 @@ public class Prerequisite {
     /**
      * The description of the requirements of the prerequisite.
      */
-    @Getter
     private final String description;
 
     /**
@@ -91,4 +133,22 @@ public class Prerequisite {
     static {
         update();
     }
+
+    /**
+     * Get if the prerequisite is met.
+     *
+     * @return If the condition is met.
+     */
+    public boolean isMet() {
+        return this.isMet;
+    }
+
+    /**
+     * Get the description.
+     *
+     * @return The description.
+     */
+    public String getDescription() {
+        return this.description;
+    }
 }

eco-api/src/main/java/com/willfp/eco/core/command/CommandBase.java

@@ -0,0 +1,116 @@
+package com.willfp.eco.core.command;
+
+import com.willfp.eco.core.EcoPlugin;
+import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Interface for all command implementations.
+ */
+public interface CommandBase {
+    /**
+     * Get command name.
+     *
+     * @return The name.
+     */
+    String getName();
+
+    /**
+     * Get command permission.
+     *
+     * @return The permission.
+     */
+    String getPermission();
+
+    /**
+     * If only players can execute the command.
+     *
+     * @return If true.
+     */
+    boolean isPlayersOnly();
+
+    /**
+     * Add a subcommand to the command.
+     *
+     * @param command The subcommand.
+     * @return The parent command.
+     */
+    CommandBase addSubcommand(@NotNull CommandBase command);
+
+    /**
+     * Handle command execution.
+     * <p>
+     * Marked as default void with no implementation for backwards compatibility.
+     *
+     * @param sender The sender.
+     * @param args   The args.
+     */
+    default void onExecute(@NotNull CommandSender sender,
+                           @NotNull List<String> args) {
+        // Do nothing.
+    }
+
+    /**
+     * Handle tab completion.
+     * <p>
+     * Marked as default void with no implementation for backwards compatibility.
+     *
+     * @param sender The sender.
+     * @param args   The args.
+     * @return The results.
+     */
+    default List<String> tabComplete(@NotNull CommandSender sender,
+                                     @NotNull List<String> args) {
+        return new ArrayList<>();
+    }
+
+    /**
+     * Get the plugin.
+     *
+     * @return The plugin.
+     */
+    EcoPlugin getPlugin();
+
+    /**
+     * Get the handler.
+     *
+     * @return The handler.
+     * @see CommandHandler
+     * @deprecated Use {@link CommandBase#onExecute(CommandSender, List)} instead.
+     */
+    @Deprecated
+    CommandHandler getHandler();
+
+    /**
+     * Set the handler.
+     *
+     * @param handler The handler.
+     * @see CommandHandler
+     * @deprecated Handlers have been deprecated.
+     */
+    @Deprecated
+    void setHandler(@NotNull CommandHandler handler);
+
+    /**
+     * Get the tab completer.
+     *
+     * @return The tab completer.
+     * @see TabCompleteHandler
+     * @deprecated Use {@link CommandBase#tabComplete(CommandSender, List)} instead.
+     */
+    @Deprecated
+    TabCompleteHandler getTabCompleter();
+
+    /**
+     * Set the tab completer.
+     *
+     * @param handler The handler.
+     * @see TabCompleteHandler
+     * @deprecated Handlers have been deprecated.
+     */
+    @Deprecated
+    void setTabCompleter(@NotNull TabCompleteHandler handler);
+}

eco-api/src/main/java/com/willfp/eco/core/command/CommandHandler.java

@@ -0,0 +1,29 @@
+package com.willfp.eco.core.command;
+
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.List;
+
+/**
+ * A command handler handles the actual code for a command.
+ * <p>
+ * The replacement for {@link org.bukkit.command.CommandExecutor#onCommand(CommandSender, Command, String, String[])}
+ *
+ * @see CommandBase
+ * @deprecated Handlers have been deprecated. This legacy system will eventually be removed,
+ * update to use the new system: {@link CommandBase#onExecute(CommandSender, List)}.
+ */
+@FunctionalInterface
+@Deprecated(since = "6.17.0")
+public interface CommandHandler {
+    /**
+     * The code to be called on execution.
+     *
+     * @param sender The sender.
+     * @param args   The arguments.
+     */
+    void onExecute(@NotNull CommandSender sender,
+                   @NotNull List<String> args);
+}

eco-api/src/main/java/com/willfp/eco/core/command/TabCompleteHandler.java

@@ -0,0 +1,30 @@
+package com.willfp.eco.core.command;
+
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.List;
+
+/**
+ * A Tab Complete handler handles the actual tab-completion code.
+ * <p>
+ * The replacement for {@link org.bukkit.command.TabCompleter#onTabComplete(CommandSender, Command, String, String[])}
+ *
+ * @see CommandBase
+ * @deprecated Handlers have been deprecated. This legacy system will eventually be removed,
+ * update to use the new system: {@link CommandBase#tabComplete(CommandSender, List)}
+ */
+@FunctionalInterface
+@Deprecated(since = "6.17.0")
+public interface TabCompleteHandler {
+    /**
+     * Handle Tab Completion.
+     *
+     * @param sender The sender.
+     * @param args   The arguments.
+     * @return The tab completion results.
+     */
+    List<String> tabComplete(@NotNull CommandSender sender,
+                             @NotNull List<String> args);
+}

eco-api/src/main/java/com/willfp/eco/core/command/impl/HandledCommand.java

@@ -0,0 +1,282 @@
+package com.willfp.eco.core.command.impl;
+
+import com.willfp.eco.core.EcoPlugin;
+import com.willfp.eco.core.command.CommandBase;
+import com.willfp.eco.core.command.CommandHandler;
+import com.willfp.eco.core.command.TabCompleteHandler;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+import org.bukkit.util.StringUtil;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
+/**
+ * Abstract class for commands that can be handled.
+ * <p>
+ * Handled commands have a method to pass in raw input from bukkit commands
+ * in order to execute the command-specific code. It's essentially an internal
+ * layer, hence why it's a package-private class.
+ */
+@SuppressWarnings({"DeprecatedIsStillUsed"})
+abstract class HandledCommand implements CommandBase {
+    /**
+     * The plugin.
+     */
+    private final EcoPlugin plugin;
+
+    /**
+     * The name of the command.
+     */
+    private final String name;
+
+    /**
+     * The permission required to execute the command.
+     * <p>
+     * Written out as a string for flexibility with subclasses.
+     */
+    private final String permission;
+
+    /**
+     * Should the command only be allowed to be executed by players?
+     * <p>
+     * In other worlds, only allowed to be executed by console.
+     */
+    private final boolean playersOnly;
+
+    /**
+     * The actual code to be executed in the command.
+     */
+    @Deprecated
+    @Nullable
+    private CommandHandler handler = null;
+
+    /**
+     * The tab completion code to be executed in the command.
+     */
+    @Deprecated
+    @Nullable
+    private TabCompleteHandler tabCompleter = null;
+
+    /**
+     * All subcommands for the command.
+     */
+    private final List<CommandBase> subcommands;
+
+    /**
+     * Create a new command.
+     * <p>
+     * The name cannot be the same as an existing command as this will conflict.
+     *
+     * @param plugin      Instance of a plugin.
+     * @param name        The name used in execution.
+     * @param permission  The permission required to execute the command.
+     * @param playersOnly If only players should be able to execute this command.
+     */
+    HandledCommand(@NotNull final EcoPlugin plugin,
+                   @NotNull final String name,
+                   @NotNull final String permission,
+                   final boolean playersOnly) {
+        this.plugin = plugin;
+        this.name = name;
+        this.permission = permission;
+        this.playersOnly = playersOnly;
+        this.subcommands = new ArrayList<>();
+    }
+
+    /**
+     * Add a subcommand to the command.
+     *
+     * @param subcommand The subcommand.
+     * @return The parent command.
+     */
+    @Override
+    public final CommandBase addSubcommand(@NotNull final CommandBase subcommand) {
+        subcommands.add(subcommand);
+
+        return this;
+    }
+
+    /**
+     * Get the plugin.
+     *
+     * @return The plugin.
+     */
+    @Override
+    public EcoPlugin getPlugin() {
+        return this.plugin;
+    }
+
+    /**
+     * Handle the command.
+     *
+     * @param sender The sender.
+     * @param args   The arguments.
+     */
+    protected final void handle(@NotNull final CommandSender sender,
+                                @NotNull final String[] args) {
+        if (!canExecute(sender, this, this.getPlugin())) {
+            return;
+        }
+
+        if (args.length > 0) {
+            for (CommandBase subcommand : this.getSubcommands()) {
+                if (subcommand.getName().equalsIgnoreCase(args[0])) {
+                    if (!canExecute(sender, subcommand, this.getPlugin())) {
+                        return;
+                    }
+
+                    ((HandledCommand) subcommand).handle(sender, Arrays.copyOfRange(args, 1, args.length));
+
+                    return;
+                }
+            }
+        }
+
+        if (this.isPlayersOnly() && !(sender instanceof Player)) {
+            sender.sendMessage(this.getPlugin().getLangYml().getMessage("not-player"));
+            return;
+        }
+
+        if (this.getHandler() != null) {
+            this.getHandler().onExecute(sender, Arrays.asList(args));
+        } else {
+            this.onExecute(sender, Arrays.asList(args));
+        }
+    }
+
+    /**
+     * Handle the tab completion.
+     *
+     * @param sender The sender.
+     * @param args   The arguments.
+     * @return The tab completion results.
+     */
+    protected final List<String> handleTabCompletion(@NotNull final CommandSender sender,
+                                                     @NotNull final String[] args) {
+
+        if (!sender.hasPermission(this.getPermission())) {
+            return null;
+        }
+
+        if (args.length == 1) {
+            List<String> completions = new ArrayList<>();
+
+            StringUtil.copyPartialMatches(
+                    args[0],
+                    this.getSubcommands().stream().map(CommandBase::getName).collect(Collectors.toList()),
+                    completions
+            );
+
+            Collections.sort(completions);
+
+            if (!completions.isEmpty()) {
+                return completions;
+            }
+        }
+
+        if (args.length >= 2) {
+            HandledCommand command = null;
+
+            for (CommandBase subcommand : this.getSubcommands()) {
+                if (args[0].equalsIgnoreCase(subcommand.getName())) {
+                    command = (HandledCommand) subcommand;
+                }
+            }
+
+            if (command != null) {
+                return command.handleTabCompletion(sender, Arrays.copyOfRange(args, 1, args.length));
+            }
+        }
+
+        if (this.getTabCompleter() != null) {
+            return this.getTabCompleter().tabComplete(sender, Arrays.asList(args));
+        } else {
+            return this.tabComplete(sender, Arrays.asList(args));
+        }
+    }
+
+    /**
+     * If a sender can execute the command.
+     *
+     * @param sender  The sender.
+     * @param command The command.
+     * @param plugin  The plugin.
+     * @return If the sender can execute.
+     */
+    public static boolean canExecute(@NotNull final CommandSender sender,
+                                     @NotNull final CommandBase command,
+                                     @NotNull final EcoPlugin plugin) {
+        if (!sender.hasPermission(command.getPermission()) && sender instanceof Player) {
+            sender.sendMessage(plugin.getLangYml().getNoPermission());
+            return false;
+        }
+
+        return true;
+    }
+
+    /**
+     * Get the command name.
+     *
+     * @return The name.
+     */
+    public String getName() {
+        return this.name;
+    }
+
+    /**
+     * Get the permission required to execute the command.
+     *
+     * @return The permission.
+     */
+    public String getPermission() {
+        return this.permission;
+    }
+
+    /**
+     * Get if the command can only be executed by players.
+     *
+     * @return If players only.
+     */
+    public boolean isPlayersOnly() {
+        return this.playersOnly;
+    }
+
+    /**
+     * Get the subcommands of the command.
+     *
+     * @return The subcommands.
+     */
+    public List<CommandBase> getSubcommands() {
+        return this.subcommands;
+    }
+
+    @Deprecated
+    @Override
+    public @Nullable CommandHandler getHandler() {
+        return this.handler;
+    }
+
+    @Deprecated
+    @Override
+    public @Nullable TabCompleteHandler getTabCompleter() {
+        return this.tabCompleter;
+    }
+
+    @Deprecated
+    @Override
+    public void setHandler(@Nullable final CommandHandler handler) {
+        this.handler = handler;
+    }
+
+    @Deprecated
+    @Override
+    public void setTabCompleter(@Nullable final TabCompleteHandler tabCompleter) {
+        this.tabCompleter = tabCompleter;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/command/impl/PluginCommand.java

@@ -0,0 +1,96 @@
+package com.willfp.eco.core.command.impl;
+
+import com.willfp.eco.core.EcoPlugin;
+import org.bukkit.Bukkit;
+import org.bukkit.command.Command;
+import org.bukkit.command.CommandExecutor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.command.TabCompleter;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.List;
+
+/**
+ * PluginCommands are the class to be used instead of CommandExecutor,
+ * they function as the base command, e.g. {@code /ecoenchants} would be a base command, with each
+ * subsequent argument functioning as subcommands.
+ * <p>
+ * The command will not be registered until register() is called.
+ * <p>
+ * The name cannot be the same as an existing command as this will conflict.
+ */
+public abstract class PluginCommand extends HandledCommand implements CommandExecutor, TabCompleter {
+    /**
+     * Create a new command.
+     *
+     * @param plugin      The plugin.
+     * @param name        The name used in execution.
+     * @param permission  The permission required to execute the command.
+     * @param playersOnly If only players should be able to execute this command.
+     */
+    protected PluginCommand(@NotNull final EcoPlugin plugin,
+                            @NotNull final String name,
+                            @NotNull final String permission,
+                            final boolean playersOnly) {
+        super(plugin, name, permission, playersOnly);
+    }
+
+    /**
+     * Registers the command with the server,
+     * <p>
+     * Requires the command name to exist, defined in plugin.yml.
+     */
+    public final void register() {
+        org.bukkit.command.PluginCommand command = Bukkit.getPluginCommand(this.getName());
+        assert command != null;
+        command.setExecutor(this);
+        command.setTabCompleter(this);
+    }
+
+    /**
+     * Internal implementation used to clean up boilerplate.
+     * Used for parity with {@link CommandExecutor#onCommand(CommandSender, Command, String, String[])}.
+     *
+     * @param sender  The executor of the command.
+     * @param command The bukkit command.
+     * @param label   The name of the executed command.
+     * @param args    The arguments of the command (anything after the physical command name)
+     * @return If the command was processed by the linked {@link EcoPlugin}
+     */
+    @Override
+    public final boolean onCommand(@NotNull final CommandSender sender,
+                                   @NotNull final Command command,
+                                   @NotNull final String label,
+                                   @NotNull final String[] args) {
+        if (!command.getName().equalsIgnoreCase(this.getName())) {
+            return false;
+        }
+
+        this.handle(sender, args);
+
+        return true;
+    }
+
+    /**
+     * Internal implementation used to clean up boilerplate.
+     * Used for parity with {@link TabCompleter#onTabComplete(CommandSender, Command, String, String[])}.
+     *
+     * @param sender  The executor of the command.
+     * @param command The bukkit command.
+     * @param label   The name of the executed command.
+     * @param args    The arguments of the command (anything after the physical command name).
+     * @return The list of tab-completions.
+     */
+    @Override
+    public @Nullable List<String> onTabComplete(@NotNull final CommandSender sender,
+                                                @NotNull final Command command,
+                                                @NotNull final String label,
+                                                @NotNull final String[] args) {
+        if (!command.getName().equalsIgnoreCase(this.getName())) {
+            return null;
+        }
+
+        return this.handleTabCompletion(sender, args);
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/command/impl/Subcommand.java

@@ -0,0 +1,38 @@
+package com.willfp.eco.core.command.impl;
+
+import com.willfp.eco.core.EcoPlugin;
+import com.willfp.eco.core.command.CommandBase;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Subcommands can be added to PluginCommands or to other Subcommands.
+ */
+public abstract class Subcommand extends HandledCommand {
+    /**
+     * Create subcommand.
+     *
+     * @param plugin      The plugin.
+     * @param name        The subcommand name.
+     * @param permission  The subcommand permission.
+     * @param playersOnly If the subcommand only works on players.
+     */
+    protected Subcommand(@NotNull final EcoPlugin plugin,
+                         @NotNull final String name,
+                         @NotNull final String permission,
+                         final boolean playersOnly) {
+        super(plugin, name, permission, playersOnly);
+    }
+
+    /**
+     * Create subcommand.
+     *
+     * @param plugin The plugin.
+     * @param name   The name of the subcommand.
+     * @param parent The parent command.
+     */
+    protected Subcommand(@NotNull final EcoPlugin plugin,
+                         @NotNull final String name,
+                         @NotNull final CommandBase parent) {
+        super(plugin, name, parent.getPermission(), parent.isPlayersOnly());
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/BaseConfig.java

@@ -0,0 +1,35 @@
+package com.willfp.eco.core.config;
+
+import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.PluginLike;
+import com.willfp.eco.core.config.wrapper.LoadableConfigWrapper;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Config implementation for configs present in the plugin's base directory (eg config.yml, lang.yml).
+ * <p>
+ * Automatically updates.
+ */
+public abstract class BaseConfig extends LoadableConfigWrapper {
+    /**
+     * Create new Base Config.
+     *
+     * @param plugin       The plugin or extension.
+     * @param configName   The config name (excluding extension).
+     * @param removeUnused If unused sections should be removed.
+     * @param type         The config type.
+     */
+    protected BaseConfig(@NotNull final String configName,
+                         @NotNull final PluginLike plugin,
+                         final boolean removeUnused,
+                         @NotNull final ConfigType type) {
+        super(Eco.getHandler().getConfigFactory().createUpdatableConfig(
+                configName,
+                plugin,
+                "",
+                plugin.getClass(),
+                removeUnused,
+                type
+        ));
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/ConfigType.java

@@ -0,0 +1,16 @@
+package com.willfp.eco.core.config;
+
+/**
+ * Config types, classified by file extension.
+ */
+public enum ConfigType {
+    /**
+     * .json config.
+     */
+    JSON,
+
+    /**
+     * .yml config.
+     */
+    YAML
+}

eco-api/src/main/java/com/willfp/eco/core/config/ExtendableConfig.java

@@ -0,0 +1,44 @@
+package com.willfp.eco.core.config;
+
+import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.PluginLike;
+import com.willfp.eco.core.config.wrapper.LoadableConfigWrapper;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Config implementation for configs present in one of two places:
+ * <ul>
+ *     <li>Plugin base directory (eg config.yml, lang.json)</li>
+ *     <li>Other extension's configs</li>
+ * </ul>
+ * <p>
+ * Automatically updates.
+ */
+public abstract class ExtendableConfig extends LoadableConfigWrapper {
+    /**
+     * @param configName       The name of the config
+     * @param removeUnused     Whether keys not present in the default config should be removed on update.
+     * @param plugin           The plugin.
+     * @param updateBlacklist  Substring of keys to not add/remove keys for.
+     * @param subDirectoryPath The subdirectory path.
+     * @param type             The config type.
+     * @param source           The class that owns the resource.
+     */
+    protected ExtendableConfig(@NotNull final String configName,
+                               final boolean removeUnused,
+                               @NotNull final PluginLike plugin,
+                               @NotNull final Class<?> source,
+                               @NotNull final String subDirectoryPath,
+                               @NotNull final ConfigType type,
+                               @NotNull final String... updateBlacklist) {
+        super(Eco.getHandler().getConfigFactory().createUpdatableConfig(
+                configName,
+                plugin,
+                subDirectoryPath,
+                source,
+                removeUnused,
+                type,
+                updateBlacklist
+        ));
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/StaticBaseConfig.java

@@ -0,0 +1,32 @@
+package com.willfp.eco.core.config;
+
+import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.PluginLike;
+import com.willfp.eco.core.config.wrapper.LoadableConfigWrapper;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Non-updatable yaml config that exists within a plugin jar.
+ */
+public abstract class StaticBaseConfig extends LoadableConfigWrapper {
+    /**
+     * Config implementation for configs present in the plugin's base directory (eg config.yml, lang.yml).
+     * <p>
+     * Does not automatically update.
+     *
+     * @param configName The name of the config
+     * @param plugin     The plugin.
+     * @param type       The config type.
+     */
+    protected StaticBaseConfig(@NotNull final String configName,
+                               @NotNull final PluginLike plugin,
+                               @NotNull final ConfigType type) {
+        super(Eco.getHandler().getConfigFactory().createLoadableConfig(
+                configName,
+                plugin,
+                "",
+                plugin.getClass(),
+                type
+        ));
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/TransientConfig.java

@@ -0,0 +1,60 @@
+package com.willfp.eco.core.config;
+
+import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.config.interfaces.Config;
+import com.willfp.eco.core.config.wrapper.ConfigWrapper;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.util.Map;
+
+/**
+ * Config that exists purely in the code, not linked to any file.
+ * <p>
+ * Use for inline configs to move data around or to add subsections to other configs.
+ */
+public class TransientConfig extends ConfigWrapper<Config> {
+    /**
+     * @param config The YamlConfiguration handle.
+     */
+    public TransientConfig(@NotNull final YamlConfiguration config) {
+        super(Eco.getHandler().getConfigFactory().createConfig(config));
+    }
+
+    /**
+     * @param stream The InputStream.
+     */
+    public TransientConfig(@Nullable final InputStream stream) {
+        super(stream != null ? Eco.getHandler().getConfigFactory().createConfig(YamlConfiguration.loadConfiguration(
+                new InputStreamReader(stream)
+        )) : new TransientConfig());
+    }
+
+    /**
+     * Create a new empty transient config.
+     *
+     * @param values The values.
+     */
+    public TransientConfig(@NotNull final Map<String, Object> values) {
+        super(Eco.getHandler().getConfigFactory().createConfig(values));
+    }
+
+    /**
+     * Create a new empty transient config.
+     */
+    public TransientConfig() {
+        super(Eco.getHandler().getConfigFactory().createConfig("", ConfigType.YAML));
+    }
+
+    /**
+     * @param contents The contents of the config.
+     * @param type     The config type.
+     */
+    public TransientConfig(@NotNull final String contents,
+                           @NotNull final ConfigType type) {
+        super(Eco.getHandler().getConfigFactory().createConfig(contents, type));
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/base/ConfigYml.java

@@ -0,0 +1,55 @@
+package com.willfp.eco.core.config.base;
+
+import com.willfp.eco.core.EcoPlugin;
+import com.willfp.eco.core.config.BaseConfig;
+import com.willfp.eco.core.config.ConfigType;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Default plugin config.yml.
+ */
+public class ConfigYml extends BaseConfig {
+    /**
+     * Config.yml.
+     *
+     * @param plugin The plugin.
+     */
+    public ConfigYml(@NotNull final EcoPlugin plugin) {
+        super("config", plugin, true, ConfigType.YAML);
+    }
+
+    /**
+     * Config.yml.
+     *
+     * @param plugin       The plugin.
+     * @param removeUnused Remove unused.
+     */
+    public ConfigYml(@NotNull final EcoPlugin plugin,
+                     final boolean removeUnused) {
+        super("config", plugin, removeUnused, ConfigType.YAML);
+    }
+
+    /**
+     * Config.yml.
+     *
+     * @param plugin The plugin.
+     * @param name   The config name.
+     */
+    public ConfigYml(@NotNull final EcoPlugin plugin,
+                     @NotNull final String name) {
+        super(name, plugin, true, ConfigType.YAML);
+    }
+
+    /**
+     * Config.yml.
+     *
+     * @param plugin       The plugin.
+     * @param name         The config name.
+     * @param removeUnused Remove unused.
+     */
+    public ConfigYml(@NotNull final EcoPlugin plugin,
+                     @NotNull final String name,
+                     final boolean removeUnused) {
+        super(name, plugin, removeUnused, ConfigType.YAML);
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/base/LangYml.java

@@ -0,0 +1,61 @@
+package com.willfp.eco.core.config.base;
+
+import com.willfp.eco.core.EcoPlugin;
+import com.willfp.eco.core.config.BaseConfig;
+import com.willfp.eco.core.config.ConfigType;
+import com.willfp.eco.util.StringUtils;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Default plugin lang.yml.
+ */
+public class LangYml extends BaseConfig {
+    /**
+     * Lang.yml.
+     *
+     * @param plugin The plugin.
+     */
+    public LangYml(@NotNull final EcoPlugin plugin) {
+        super("lang", plugin, false, ConfigType.YAML);
+    }
+
+    /**
+     * Get the prefix for messages in chat.
+     *
+     * @return The prefix.
+     */
+    public String getPrefix() {
+        return this.getFormattedString("messages.prefix");
+    }
+
+    /**
+     * Get the no permission message.
+     *
+     * @return The message.
+     */
+    public String getNoPermission() {
+        return getPrefix() + this.getFormattedString("messages.no-permission");
+    }
+
+    /**
+     * Get a chat message.
+     *
+     * @param message The key of the message.
+     * @return The message with a prefix appended.
+     */
+    public String getMessage(@NotNull final String message) {
+        return getMessage(message, StringUtils.FormatOption.WITH_PLACEHOLDERS);
+    }
+
+    /**
+     * Get a chat message.
+     *
+     * @param message The key of the message.
+     * @param option  The format options.
+     * @return The message with a prefix appended.
+     */
+    public String getMessage(@NotNull final String message,
+                             @NotNull final StringUtils.FormatOption option) {
+        return getPrefix() + this.getFormattedString("messages." + message, option);
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/interfaces/Config.java

@@ -0,0 +1,632 @@
+package com.willfp.eco.core.config.interfaces;
+
+import com.willfp.eco.core.config.ConfigType;
+import com.willfp.eco.core.config.TransientConfig;
+import com.willfp.eco.util.NumberUtils;
+import com.willfp.eco.util.StringUtils;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * All configs implement this interface.
+ * <p>
+ * Contains all methods that must exist in yaml and json configurations.
+ */
+@SuppressWarnings("unused")
+public interface Config extends Cloneable {
+    /**
+     * Clears cache.
+     */
+    void clearCache();
+
+    /**
+     * Convert the config into readable text.
+     *
+     * @return The plaintext.
+     */
+    String toPlaintext();
+
+    /**
+     * Get if the config contains a key.
+     *
+     * @param path The key to check.
+     * @return If contained.
+     */
+    boolean has(@NotNull String path);
+
+    /**
+     * Get config keys.
+     *
+     * @param deep If keys from subsections should be fetched too.
+     * @return A list of keys.
+     */
+    @NotNull
+    List<String> getKeys(boolean deep);
+
+    /**
+     * Get an object from config.
+     * Default implementations call {@link org.bukkit.configuration.file.YamlConfiguration#get(String)}.
+     *
+     * @param path The path.
+     * @return The object.
+     */
+    @Nullable
+    Object get(@NotNull String path);
+
+    /**
+     * Set an object in config.
+     * Default implementations call {@link org.bukkit.configuration.file.YamlConfiguration#set(String, Object)}
+     *
+     * @param path   The path.
+     * @param object The object.
+     */
+    void set(@NotNull String path,
+             @Nullable Object object);
+
+    /**
+     * Get subsection from config.
+     *
+     * @param path The key to check.
+     * @return The subsection. Returns an empty section if not found.
+     */
+    @NotNull
+    default Config getSubsection(@NotNull String path) {
+        return Objects.requireNonNullElse(getSubsectionOrNull(path), new TransientConfig());
+    }
+
+    /**
+     * Get subsection from config.
+     *
+     * @param path The key to check.
+     * @return The subsection, or null if not found.
+     */
+    @Nullable
+    Config getSubsectionOrNull(@NotNull String path);
+
+    /**
+     * Get an integer from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or 0 if not found.
+     */
+    default int getInt(@NotNull String path) {
+        return Objects.requireNonNullElse(getIntOrNull(path), 0);
+    }
+
+    /**
+     * Get an integer from config with a specified default (not found) value.
+     *
+     * @param path The key to fetch the value from.
+     * @param def  The value to default to if not found.
+     * @return The found value, or the default.
+     */
+    default int getInt(@NotNull String path,
+                       int def) {
+        return Objects.requireNonNullElse(getIntOrNull(path), def);
+    }
+
+    /**
+     * Get a decimal value via a mathematical expression.
+     *
+     * @param path The key to fetch the value from.
+     * @return The computed value, or 0 if not found or invalid.
+     */
+    default int getIntFromExpression(@NotNull String path) {
+        return getIntFromExpression(path, null);
+    }
+
+    /**
+     * Get a decimal value via a mathematical expression.
+     *
+     * @param path   The key to fetch the value from.
+     * @param player The player to evaluate placeholders with respect to.
+     * @return The computed value, or 0 if not found or invalid.
+     */
+    default int getIntFromExpression(@NotNull String path,
+                                     @Nullable Player player) {
+        return Double.valueOf(getDoubleFromExpression(path, player)).intValue();
+    }
+
+
+    /**
+     * Get an integer from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or null if not found.
+     */
+    @Nullable
+    Integer getIntOrNull(@NotNull String path);
+
+    /**
+     * Get a list of integers from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or a blank {@link java.util.ArrayList} if not found.
+     */
+    @NotNull
+    default List<Integer> getInts(@NotNull String path) {
+        return Objects.requireNonNullElse(getIntsOrNull(path), new ArrayList<>());
+    }
+
+    /**
+     * Get a list of integers from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or null if not found.
+     */
+    @Nullable
+    List<Integer> getIntsOrNull(@NotNull String path);
+
+    /**
+     * Get a boolean from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or false if not found.
+     */
+    default boolean getBool(@NotNull String path) {
+        return Objects.requireNonNullElse(getBoolOrNull(path), false);
+    }
+
+    /**
+     * Get a boolean from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or null if not found.
+     */
+    @Nullable
+    Boolean getBoolOrNull(@NotNull String path);
+
+    /**
+     * Get a list of booleans from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or a blank {@link java.util.ArrayList} if not found.
+     */
+    @NotNull
+    default List<Boolean> getBools(@NotNull String path) {
+        return Objects.requireNonNullElse(getBoolsOrNull(path), new ArrayList<>());
+    }
+
+    /**
+     * Get a list of booleans from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or null if not found.
+     */
+    @Nullable
+    List<Boolean> getBoolsOrNull(@NotNull String path);
+
+    /**
+     * Get a formatted string from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or an empty string if not found.
+     */
+    @NotNull
+    default String getFormattedString(@NotNull String path) {
+        return getString(path, true, StringUtils.FormatOption.WITH_PLACEHOLDERS);
+    }
+
+    /**
+     * Get a formatted string from config.
+     *
+     * @param path   The key to fetch the value from.
+     * @param option The format option.
+     * @return The found value, or an empty string if not found.
+     */
+    @NotNull
+    default String getFormattedString(@NotNull String path,
+                                      @NotNull StringUtils.FormatOption option) {
+        return getString(path, true, option);
+    }
+
+    /**
+     * Get a string from config.
+     * <p>
+     * Not formatted.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or an empty string if not found.
+     */
+    @NotNull
+    default String getString(@NotNull String path) {
+        return getString(path, false, StringUtils.FormatOption.WITHOUT_PLACEHOLDERS);
+    }
+
+    /**
+     * Get a string from config.
+     *
+     * @param path   The key to fetch the value from.
+     * @param format If the string should be formatted.
+     * @return The found value, or an empty string if not found.
+     * @deprecated Since 6.18.0, {@link Config#getString(String)} is not formatted by default.
+     */
+    @Deprecated(since = "6.18.0")
+    default String getString(@NotNull String path,
+                             boolean format) {
+        return this.getString(path, format, StringUtils.FormatOption.WITH_PLACEHOLDERS);
+    }
+
+    /**
+     * Get a string from config.
+     *
+     * @param path   The key to fetch the value from.
+     * @param option The format option.
+     * @return The found value, or an empty string if not found.
+     * @deprecated Use {@link Config#getFormattedString(String, StringUtils.FormatOption)} instead.
+     */
+    @NotNull
+    @Deprecated
+    default String getString(@NotNull String path,
+                             @NotNull final StringUtils.FormatOption option) {
+        return this.getString(path, true, option);
+    }
+
+    /**
+     * Get a string from config.
+     *
+     * @param path   The key to fetch the value from.
+     * @param format If the string should be formatted.
+     * @param option The format option.
+     * @return The found value, or an empty string if not found.
+     */
+    @NotNull
+    default String getString(@NotNull String path,
+                             boolean format,
+                             @NotNull StringUtils.FormatOption option) {
+        return Objects.requireNonNullElse(getStringOrNull(path, format, option), "");
+    }
+
+    /**
+     * Get a formatted string from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or an empty string if not found.
+     */
+    @Nullable
+    default String getFormattedStringOrNull(@NotNull String path) {
+        return getStringOrNull(path, true, StringUtils.FormatOption.WITH_PLACEHOLDERS);
+    }
+
+    /**
+     * Get a formatted string from config.
+     *
+     * @param path   The key to fetch the value from.
+     * @param option The format option.
+     * @return The found value, or an empty string if not found.
+     */
+    @Nullable
+    default String getFormattedStringOrNull(@NotNull String path,
+                                            @NotNull StringUtils.FormatOption option) {
+        return getStringOrNull(path, true, option);
+    }
+
+    /**
+     * Get a string from config.
+     * <p>
+     * Formatted by default.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or null if not found.
+     */
+    @Nullable
+    default String getStringOrNull(@NotNull String path) {
+        return getStringOrNull(path, false, StringUtils.FormatOption.WITH_PLACEHOLDERS);
+    }
+
+    /**
+     * Get a string from config.
+     *
+     * @param path   The key to fetch the value from.
+     * @param format If the string should be formatted.
+     * @return The found value, or null if not found.
+     * @deprecated Since 6.18.0, {@link Config#getString(String)} is not formatted by default.
+     */
+    @Nullable
+    @Deprecated(since = "6.18.0")
+    default String getStringOrNull(@NotNull String path,
+                                   boolean format) {
+        return this.getStringOrNull(path, format, StringUtils.FormatOption.WITH_PLACEHOLDERS);
+    }
+
+    /**
+     * Get a string from config.
+     *
+     * @param path   The key to fetch the value from.
+     * @param option The format option.
+     * @return The found value, or null if not found.
+     * @deprecated Use {@link Config#getFormattedString(String, StringUtils.FormatOption)} instead.
+     */
+    @Nullable
+    @Deprecated
+    default String getStringOrNull(@NotNull String path,
+                                   @NotNull StringUtils.FormatOption option) {
+        return this.getStringOrNull(path, true, option);
+    }
+
+    /**
+     * Get a string from config.
+     *
+     * @param path   The key to fetch the value from.
+     * @param format If the string should be formatted.
+     * @param option The format option. If format is false, this will be ignored.
+     * @return The found value, or null if not found.
+     */
+    @Nullable
+    String getStringOrNull(@NotNull String path,
+                           boolean format,
+                           @NotNull StringUtils.FormatOption option);
+
+    /**
+     * Get a list of strings from config.
+     * <p>
+     * Formatted by default.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or a blank {@link java.util.ArrayList} if not found.
+     */
+    @NotNull
+    default List<String> getFormattedStrings(@NotNull String path) {
+        return getStrings(path, true, StringUtils.FormatOption.WITH_PLACEHOLDERS);
+    }
+
+    /**
+     * Get a list of strings from config.
+     * <p>
+     * Formatted by default.
+     *
+     * @param path   The key to fetch the value from.
+     * @param option The format option.
+     * @return The found value, or a blank {@link java.util.ArrayList} if not found.
+     */
+    @NotNull
+    default List<String> getFormattedStrings(@NotNull String path,
+                                             @NotNull StringUtils.FormatOption option) {
+        return getStrings(path, true, option);
+    }
+
+    /**
+     * Get a list of strings from config.
+     * <p>
+     * Not formatted.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or a blank {@link java.util.ArrayList} if not found.
+     */
+    @NotNull
+    default List<String> getStrings(@NotNull String path) {
+        return getStrings(path, false, StringUtils.FormatOption.WITH_PLACEHOLDERS);
+    }
+
+    /**
+     * Get a list of strings from config.
+     *
+     * @param path   The key to fetch the value from.
+     * @param format If the strings should be formatted.
+     * @return The found value, or a blank {@link java.util.ArrayList} if not found.
+     * @deprecated Since 6.18.0, {@link Config#getString(String)} is not formatted by default.
+     */
+    @NotNull
+    @Deprecated(since = "6.18.0")
+    default List<String> getStrings(@NotNull String path,
+                                    boolean format) {
+        return this.getStrings(path, format, StringUtils.FormatOption.WITH_PLACEHOLDERS);
+    }
+
+    /**
+     * Get a list of strings from config.
+     *
+     * @param path   The key to fetch the value from.
+     * @param option The format option.
+     * @return The found value, or a blank {@link java.util.ArrayList} if not found.
+     * @deprecated Use {@link Config#getFormattedStrings(String, StringUtils.FormatOption)} instead.
+     */
+    @NotNull
+    @Deprecated
+    default List<String> getStrings(@NotNull String path,
+                                    @NotNull StringUtils.FormatOption option) {
+        return getStrings(path, false, option);
+    }
+
+    /**
+     * Get a list of strings from config.
+     *
+     * @param path   The key to fetch the value from.
+     * @param format If the strings should be formatted.
+     * @param option The option.
+     * @return The found value, or a blank {@link java.util.ArrayList} if not found.
+     */
+    @NotNull
+    default List<String> getStrings(@NotNull String path,
+                                    boolean format,
+                                    @NotNull StringUtils.FormatOption option) {
+        return Objects.requireNonNullElse(getStringsOrNull(path, format, option), new ArrayList<>());
+    }
+
+    /**
+     * Get a list of strings from config.
+     * <p>
+     * Formatted.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or null if not found.
+     */
+    @Nullable
+    default List<String> getFormattedStringsOrNull(@NotNull String path) {
+        return getStringsOrNull(path, true, StringUtils.FormatOption.WITH_PLACEHOLDERS);
+    }
+
+    /**
+     * Get a list of strings from config.
+     * <p>
+     * Formatted.
+     *
+     * @param path   The key to fetch the value from.
+     * @param option The format option.
+     * @return The found value, or null if not found.
+     */
+    @Nullable
+    default List<String> getFormattedStringsOrNull(@NotNull String path,
+                                                   @NotNull StringUtils.FormatOption option) {
+        return getStringsOrNull(path, true, option);
+    }
+
+    /**
+     * Get a list of strings from config.
+     * <p>
+     * Not formatted.
+     * <p>
+     * This will be changed in newer versions to <b>not</b> format by default.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or null if not found.
+     */
+    @Nullable
+    default List<String> getStringsOrNull(@NotNull String path) {
+        return getStringsOrNull(path, false, StringUtils.FormatOption.WITH_PLACEHOLDERS);
+    }
+
+    /**
+     * Get a list of strings from config.
+     *
+     * @param path   The key to fetch the value from.
+     * @param format If the strings should be formatted.
+     * @return The found value, or null if not found.
+     * @deprecated Since 6.18.0, {@link Config#getString(String)} is not formatted by default.
+     */
+    @Nullable
+    @Deprecated(since = "6.18.0")
+    default List<String> getStringsOrNull(@NotNull String path,
+                                          boolean format) {
+        return getStringsOrNull(path, format, StringUtils.FormatOption.WITH_PLACEHOLDERS);
+    }
+
+    /**
+     * Get a list of strings from config.
+     *
+     * @param path   The key to fetch the value from.
+     * @param option The format option.
+     * @return The found value, or null if not found.
+     * @deprecated Use {@link Config#getFormattedStringsOrNull(String, StringUtils.FormatOption)} instead.
+     */
+    @Nullable
+    @Deprecated
+    default List<String> getStringsOrNull(@NotNull String path,
+                                          @NotNull StringUtils.FormatOption option) {
+        return getStringsOrNull(path, false, option);
+    }
+
+    /**
+     * Get a list of strings from config.
+     *
+     * @param path   The key to fetch the value from.
+     * @param format If the strings should be formatted.
+     * @param option The format option.
+     * @return The found value, or null if not found.
+     */
+    @Nullable
+    List<String> getStringsOrNull(@NotNull String path,
+                                  boolean format,
+                                  @NotNull StringUtils.FormatOption option);
+
+    /**
+     * Get a decimal from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or 0 if not found.
+     */
+    default double getDouble(@NotNull String path) {
+        return Objects.requireNonNullElse(getDoubleOrNull(path), 0.0);
+    }
+
+    /**
+     * Get a decimal value via a mathematical expression.
+     *
+     * @param path The key to fetch the value from.
+     * @return The computed value, or 0 if not found or invalid.
+     */
+    default double getDoubleFromExpression(@NotNull String path) {
+        return getDoubleFromExpression(path, null);
+    }
+
+    /**
+     * Get a decimal value via a mathematical expression.
+     *
+     * @param path   The key to fetch the value from.
+     * @param player The player to evaluate placeholders with respect to.
+     * @return The computed value, or 0 if not found or invalid.
+     */
+    default double getDoubleFromExpression(@NotNull String path,
+                                           @Nullable Player player) {
+        return NumberUtils.evaluateExpression(this.getString(path), player);
+    }
+
+    /**
+     * Get a decimal from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or null if not found.
+     */
+    @Nullable
+    Double getDoubleOrNull(@NotNull String path);
+
+    /**
+     * Get a list of decimals from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or a blank {@link java.util.ArrayList} if not found.
+     */
+    @NotNull
+    default List<Double> getDoubles(@NotNull String path) {
+        return Objects.requireNonNullElse(getDoublesOrNull(path), new ArrayList<>());
+    }
+
+    /**
+     * Get a list of decimals from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or null if not found.
+     */
+    @Nullable
+    List<Double> getDoublesOrNull(@NotNull String path);
+
+    /**
+     * Get a list of subsections from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or a blank {@link java.util.ArrayList} if not found.
+     */
+    @NotNull
+    default List<? extends Config> getSubsections(@NotNull String path) {
+        return Objects.requireNonNullElse(getSubsectionsOrNull(path), new ArrayList<>());
+    }
+
+    /**
+     * Get a list of subsections from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or null if not found.
+     */
+    @Nullable
+    List<? extends Config> getSubsectionsOrNull(@NotNull String path);
+
+    /**
+     * Get config type.
+     *
+     * @return The type.
+     */
+    @NotNull
+    ConfigType getType();
+
+    /**
+     * Clone the config.
+     *
+     * @return The clone.
+     */
+    Config clone();
+}

eco-api/src/main/java/com/willfp/eco/core/config/interfaces/JSONConfig.java

@@ -0,0 +1,63 @@
+package com.willfp.eco.core.config.interfaces;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * JSON config.
+ *
+ * @deprecated JSON and yml have full parity, use configs without a prefix instead,
+ * eg {@link com.willfp.eco.core.config.TransientConfig}, {@link com.willfp.eco.core.config.BaseConfig}.
+ * These configs will be removed eventually.
+ */
+@Deprecated(since = "6.17.0")
+@SuppressWarnings("DeprecatedIsStillUsed")
+public interface JSONConfig extends Config {
+    /**
+     * Get a list of subsections from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or a blank {@link java.util.ArrayList} if not found.
+     */
+    @NotNull
+    default List<JSONConfig> getSubsections(@NotNull String path) {
+        return Objects.requireNonNullElse(getSubsectionsOrNull(path), new ArrayList<>());
+    }
+
+    /**
+     * Get a list of subsections from config.
+     *
+     * @param path The key to fetch the value from.
+     * @return The found value, or null if not found.
+     */
+    @Nullable
+    List<JSONConfig> getSubsectionsOrNull(@NotNull String path);
+
+
+    /**
+     * Get subsection from config.
+     *
+     * @param path The key to check.
+     * @return The subsection. Throws NPE if not found.
+     */
+    @Override
+    @NotNull
+    JSONConfig getSubsection(@NotNull String path);
+
+    /**
+     * Get subsection from config.
+     *
+     * @param path The key to check.
+     * @return The subsection, or null if not found.
+     */
+    @Override
+    @Nullable
+    JSONConfig getSubsectionOrNull(@NotNull String path);
+
+    @Override
+    JSONConfig clone();
+}

eco-api/src/main/java/com/willfp/eco/core/config/interfaces/LoadableConfig.java

@@ -0,0 +1,60 @@
+package com.willfp.eco.core.config.interfaces;
+
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.bukkit.plugin.java.JavaPlugin;
+import org.jetbrains.annotations.Nullable;
+
+import java.io.File;
+import java.io.IOException;
+
+/**
+ * Interface for configs that physically exist as files in plugins.
+ */
+public interface LoadableConfig extends Config {
+    /**
+     * Create the file.
+     */
+    void createFile();
+
+    /**
+     * Get resource path as relative to base directory.
+     *
+     * @return The resource path.
+     */
+    String getResourcePath();
+
+    /**
+     * Save the config.
+     *
+     * @throws IOException If error in saving.
+     */
+    void save() throws IOException;
+
+    /**
+     * Get the config file.
+     *
+     * @return The file.
+     */
+    File getConfigFile();
+
+    /**
+     * Get the config name (including extension).
+     *
+     * @return The name.
+     */
+    String getName();
+
+    /**
+     * Get bukkit {@link YamlConfiguration}.
+     * <p>
+     * This method is not recommended unless absolutely required as it
+     * only returns true if the type of config is {@link com.willfp.eco.core.config.ConfigType#YAML},
+     * and if the handle is an {@link YamlConfiguration} specifically. This depends on the internals
+     * and the implementation, and so may cause problems - it exists mostly for parity with
+     * {@link JavaPlugin#getConfig()}.
+     *
+     * @return The config, or null if config is not yaml-based.
+     */
+    @Nullable
+    YamlConfiguration getBukkitHandle();
+}

eco-api/src/main/java/com/willfp/eco/core/config/interfaces/WrappedYamlConfiguration.java

@@ -0,0 +1,21 @@
+package com.willfp.eco.core.config.interfaces;
+
+import org.bukkit.configuration.file.YamlConfiguration;
+
+/**
+ * Interface for configs that wrap an {@link YamlConfiguration}.
+ *
+ * @deprecated JSON and yml have full parity, use configs without a prefix instead,
+ * eg {@link com.willfp.eco.core.config.TransientConfig}, {@link com.willfp.eco.core.config.BaseConfig}.
+ * These configs will be removed eventually.
+ */
+@Deprecated(since = "6.17.0")
+@SuppressWarnings("DeprecatedIsStillUsed")
+public interface WrappedYamlConfiguration {
+    /**
+     * Get the ConfigurationSection handle.
+     *
+     * @return The handle.
+     */
+    YamlConfiguration getBukkitHandle();
+}

eco-api/src/main/java/com/willfp/eco/core/config/json/JSONBaseConfig.java

@@ -0,0 +1,90 @@
+package com.willfp.eco.core.config.json;
+
+import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.EcoPlugin;
+import com.willfp.eco.core.PluginLike;
+import com.willfp.eco.core.config.ConfigType;
+import com.willfp.eco.core.config.interfaces.JSONConfig;
+import com.willfp.eco.core.config.json.wrapper.LoadableJSONConfigWrapper;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Config implementation for configs present in the plugin's base directory (eg config.json).
+ * <p>
+ * Automatically updates.
+ *
+ * @deprecated JSON and yml have full parity, use configs without a prefix instead,
+ * eg {@link com.willfp.eco.core.config.TransientConfig}, {@link com.willfp.eco.core.config.BaseConfig}.
+ * These configs will be removed eventually.
+ */
+@Deprecated(since = "6.17.0")
+public abstract class JSONBaseConfig extends LoadableJSONConfigWrapper {
+    /**
+     * @param configName      The name of the config
+     * @param removeUnused    Whether keys not present in the default config should be removed on update.
+     * @param plugin          The plugin.
+     * @param updateBlacklist Substring of keys to not add/remove keys for.
+     */
+    protected JSONBaseConfig(@NotNull final String configName,
+                             final boolean removeUnused,
+                             @NotNull final PluginLike plugin,
+                             @NotNull final String... updateBlacklist) {
+        super(
+                (JSONConfig)
+                        Eco.getHandler().getConfigFactory().createUpdatableConfig(
+                                configName,
+                                plugin,
+                                "",
+                                plugin.getClass(),
+                                removeUnused,
+                                ConfigType.JSON,
+                                updateBlacklist
+                        )
+        );
+    }
+
+    /**
+     * @param configName   The name of the config
+     * @param removeUnused Whether keys not present in the default config should be removed on update.
+     * @param plugin       The plugin.
+     */
+    protected JSONBaseConfig(@NotNull final String configName,
+                             final boolean removeUnused,
+                             @NotNull final PluginLike plugin) {
+        super(
+                (JSONConfig)
+                        Eco.getHandler().getConfigFactory().createUpdatableConfig(
+                                configName,
+                                plugin,
+                                "",
+                                plugin.getClass(),
+                                removeUnused,
+                                ConfigType.JSON
+                        )
+        );
+    }
+
+    /**
+     * @param configName      The name of the config
+     * @param removeUnused    Whether keys not present in the default config should be removed on update.
+     * @param plugin          The plugin.
+     * @param updateBlacklist Substring of keys to not add/remove keys for.
+     */
+    protected JSONBaseConfig(@NotNull final String configName,
+                             final boolean removeUnused,
+                             @NotNull final EcoPlugin plugin,
+                             @NotNull final String... updateBlacklist) {
+        this(configName, removeUnused, (PluginLike) plugin, updateBlacklist);
+    }
+
+    /**
+     * @param configName   The name of the config
+     * @param removeUnused Whether keys not present in the default config should be removed on update.
+     * @param plugin       The plugin.
+     */
+    protected JSONBaseConfig(@NotNull final String configName,
+                             final boolean removeUnused,
+                             @NotNull final EcoPlugin plugin) {
+        this(configName, removeUnused, (PluginLike) plugin);
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/json/JSONExtendableConfig.java

@@ -0,0 +1,70 @@
+package com.willfp.eco.core.config.json;
+
+import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.EcoPlugin;
+import com.willfp.eco.core.PluginLike;
+import com.willfp.eco.core.config.ConfigType;
+import com.willfp.eco.core.config.interfaces.JSONConfig;
+import com.willfp.eco.core.config.json.wrapper.LoadableJSONConfigWrapper;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Config implementation for configs present in one of two places:
+ * <ul>
+ *     <li>Plugin base directory (eg config.yml, lang.yml)</li>
+ *     <li>Other extension's configs</li>
+ * </ul>
+ * <p>
+ * Automatically updates.
+ *
+ * @deprecated JSON and yml have full parity, use configs without a prefix instead,
+ * eg {@link com.willfp.eco.core.config.TransientConfig}, {@link com.willfp.eco.core.config.BaseConfig}.
+ * These configs will be removed eventually.
+ */
+@Deprecated(since = "6.17.0")
+public abstract class JSONExtendableConfig extends LoadableJSONConfigWrapper {
+    /**
+     * @param configName       The name of the config
+     * @param removeUnused     Whether keys not present in the default config should be removed on update.
+     * @param plugin           The plugin.
+     * @param updateBlacklist  Substring of keys to not add/remove keys for.
+     * @param subDirectoryPath The subdirectory path.
+     * @param source           The class that owns the resource.
+     */
+    protected JSONExtendableConfig(@NotNull final String configName,
+                                   final boolean removeUnused,
+                                   @NotNull final PluginLike plugin,
+                                   @NotNull final Class<?> source,
+                                   @NotNull final String subDirectoryPath,
+                                   @NotNull final String... updateBlacklist) {
+        super(
+                (JSONConfig)
+                        Eco.getHandler().getConfigFactory().createUpdatableConfig(
+                                configName,
+                                plugin,
+                                subDirectoryPath,
+                                source,
+                                removeUnused,
+                                ConfigType.JSON,
+                                updateBlacklist
+                        )
+        );
+    }
+
+    /**
+     * @param configName       The name of the config
+     * @param removeUnused     Whether keys not present in the default config should be removed on update.
+     * @param plugin           The plugin.
+     * @param updateBlacklist  Substring of keys to not add/remove keys for.
+     * @param subDirectoryPath The subdirectory path.
+     * @param source           The class that owns the resource.
+     */
+    protected JSONExtendableConfig(@NotNull final String configName,
+                                   final boolean removeUnused,
+                                   @NotNull final EcoPlugin plugin,
+                                   @NotNull final Class<?> source,
+                                   @NotNull final String subDirectoryPath,
+                                   @NotNull final String... updateBlacklist) {
+        this(configName, removeUnused, (PluginLike) plugin, source, subDirectoryPath, updateBlacklist);
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/json/JSONStaticBaseConfig.java

@@ -0,0 +1,45 @@
+package com.willfp.eco.core.config.json;
+
+import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.EcoPlugin;
+import com.willfp.eco.core.PluginLike;
+import com.willfp.eco.core.config.ConfigType;
+import com.willfp.eco.core.config.interfaces.JSONConfig;
+import com.willfp.eco.core.config.json.wrapper.LoadableJSONConfigWrapper;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Non-updatable JSON config that exists within a plugin jar.
+ *
+ * @deprecated JSON and yml have full parity, use configs without a prefix instead,
+ * eg {@link com.willfp.eco.core.config.TransientConfig}, {@link com.willfp.eco.core.config.BaseConfig}.
+ * These configs will be removed eventually.
+ */
+@Deprecated(since = "6.17.0")
+public abstract class JSONStaticBaseConfig extends LoadableJSONConfigWrapper {
+    /**
+     * Config implementation for configs present in the plugin's base directory (eg config.json, lang.json).
+     * <p>
+     * Does not automatically update.
+     *
+     * @param configName The name of the config
+     * @param plugin     The plugin.
+     */
+    protected JSONStaticBaseConfig(@NotNull final String configName,
+                                   @NotNull final PluginLike plugin) {
+        super((JSONConfig) Eco.getHandler().getConfigFactory().createLoadableConfig(configName, plugin, "", plugin.getClass(), ConfigType.JSON));
+    }
+
+    /**
+     * Config implementation for configs present in the plugin's base directory (eg config.json, lang.json).
+     * <p>
+     * Does not automatically update.
+     *
+     * @param configName The name of the config
+     * @param plugin     The plugin.
+     */
+    protected JSONStaticBaseConfig(@NotNull final String configName,
+                                   @NotNull final EcoPlugin plugin) {
+        this(configName, (PluginLike) plugin);
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/json/JSONTransientConfig.java

@@ -0,0 +1,37 @@
+package com.willfp.eco.core.config.json;
+
+import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.config.interfaces.JSONConfig;
+import com.willfp.eco.core.config.json.wrapper.JSONConfigWrapper;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Raw JSON config with a map of values at its core.
+ *
+ * @deprecated JSON and yml have full parity, use configs without a prefix instead,
+ * eg {@link com.willfp.eco.core.config.TransientConfig}, {@link com.willfp.eco.core.config.BaseConfig}.
+ * These configs will be removed eventually.
+ */
+@Deprecated(since = "6.17.0")
+public class JSONTransientConfig extends JSONConfigWrapper {
+    /**
+     * Config implementation for passing maps.
+     * <p>
+     * Does not automatically update.
+     *
+     * @param values The map of values.
+     */
+    public JSONTransientConfig(@NotNull final Map<String, Object> values) {
+        super((JSONConfig) Eco.getHandler().getConfigFactory().createConfig(values));
+    }
+
+    /**
+     * Empty JSON config.
+     */
+    public JSONTransientConfig() {
+        super((JSONConfig) Eco.getHandler().getConfigFactory().createConfig(new HashMap<>()));
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/json/wrapper/JSONConfigWrapper.java

@@ -0,0 +1,53 @@
+package com.willfp.eco.core.config.json.wrapper;
+
+import com.willfp.eco.core.config.interfaces.JSONConfig;
+import com.willfp.eco.core.config.wrapper.ConfigWrapper;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.List;
+
+/**
+ * Wrapper to handle the backend JSON config implementations.
+ *
+ * @deprecated JSON and yml have full parity, use configs without a prefix instead,
+ * eg {@link com.willfp.eco.core.config.TransientConfig}, {@link com.willfp.eco.core.config.BaseConfig}.
+ * These configs will be removed eventually.
+ */
+@Deprecated(since = "6.17.0")
+public abstract class JSONConfigWrapper extends ConfigWrapper<JSONConfig> implements JSONConfig {
+    /**
+     * Create a config wrapper.
+     *
+     * @param handle The handle.
+     */
+    protected JSONConfigWrapper(@NotNull final JSONConfig handle) {
+        super(handle);
+    }
+
+
+    @Override
+    public @NotNull List<JSONConfig> getSubsections(@NotNull final String path) {
+        return this.getHandle().getSubsections(path);
+    }
+
+    @Override
+    public @Nullable List<JSONConfig> getSubsectionsOrNull(@NotNull final String path) {
+        return this.getHandle().getSubsectionsOrNull(path);
+    }
+
+    @Override
+    public @NotNull JSONConfig getSubsection(@NotNull final String path) {
+        return this.getHandle().getSubsection(path);
+    }
+
+    @Override
+    public @Nullable JSONConfig getSubsectionOrNull(@NotNull final String path) {
+        return this.getHandle().getSubsectionOrNull(path);
+    }
+
+    @Override
+    public JSONConfig clone() {
+        return this.getHandle().clone();
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/json/wrapper/LoadableJSONConfigWrapper.java

@@ -0,0 +1,63 @@
+package com.willfp.eco.core.config.json.wrapper;
+
+import com.willfp.eco.core.config.interfaces.JSONConfig;
+import com.willfp.eco.core.config.interfaces.LoadableConfig;
+import org.apache.commons.lang.Validate;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.io.File;
+import java.io.IOException;
+
+/**
+ * Wrapper to handle the backend loadable JSON config implementations.
+ *
+ * @deprecated JSON and yml have full parity, use configs without a prefix instead,
+ * eg {@link com.willfp.eco.core.config.TransientConfig}, {@link com.willfp.eco.core.config.BaseConfig}.
+ * These configs will be removed eventually.
+ */
+@Deprecated(since = "6.17.0")
+public abstract class LoadableJSONConfigWrapper extends JSONConfigWrapper implements LoadableConfig {
+    /**
+     * Create a config wrapper.
+     *
+     * @param handle The handle.
+     */
+    protected LoadableJSONConfigWrapper(@NotNull final JSONConfig handle) {
+        super(handle);
+
+        Validate.isTrue(handle instanceof LoadableConfig, "Wrapped config must be loadable!");
+    }
+
+
+    @Override
+    public void createFile() {
+        ((LoadableConfig) this.getHandle()).createFile();
+    }
+
+    @Override
+    public String getResourcePath() {
+        return ((LoadableConfig) this.getHandle()).getResourcePath();
+    }
+
+    @Override
+    public void save() throws IOException {
+        ((LoadableConfig) this.getHandle()).save();
+    }
+
+    @Override
+    public File getConfigFile() {
+        return ((LoadableConfig) this.getHandle()).getConfigFile();
+    }
+
+    @Override
+    public String getName() {
+        return ((LoadableConfig) this.getHandle()).getName();
+    }
+
+    @Override
+    public @Nullable YamlConfiguration getBukkitHandle() {
+        return null;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/updating/ConfigHandler.java

@@ -0,0 +1,33 @@
+package com.willfp.eco.core.config.updating;
+
+import com.willfp.eco.core.config.interfaces.LoadableConfig;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Every {@link com.willfp.eco.core.PluginLike} has a config handler.
+ * <p>
+ * Handles updating and saving configs.
+ */
+public interface ConfigHandler {
+    /**
+     * Invoke all update methods.
+     */
+    void callUpdate();
+
+    /**
+     * Save all configs.
+     */
+    void saveAllConfigs();
+
+    /**
+     * Update all updatable configs.
+     */
+    void updateConfigs();
+
+    /**
+     * Add new config to be saved.
+     *
+     * @param config The config.
+     */
+    void addConfig(@NotNull LoadableConfig config);
+}

eco-api/src/main/java/com/willfp/eco/core/config/updating/ConfigUpdater.java

@@ -0,0 +1,43 @@
+package com.willfp.eco.core.config.updating;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Annotation to put on update methods.
+ * <p>
+ * All update methods must be public and static,
+ * and can accept an EcoPlugin as a parameter.
+ * <p>
+ * As such, there are only 2 valid update methods:
+ * <p>
+ * The first:
+ * <pre>{@code
+ * @ConfigUpdater
+ * public static void update() {
+ *     // Update code
+ * }
+ * }</pre>
+ * <p>
+ * The second:
+ * <pre>{@code
+ * public static void update(EcoPlugin plugin) {
+ *     // Update code
+ * }
+ * }</pre>
+ * <p>
+ * If using kotlin, you have to annotate the method with {@code @JvmStatic}
+ * in order to prevent null pointer exceptions.
+ * <p>
+ * Config update methods in all classes in a plugin jar will be called
+ * on reload.
+ * <p>
+ * By having a plugin as a parameter, you shouldn't really need getInstance()
+ * calls in your code.
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.METHOD)
+public @interface ConfigUpdater {
+}

eco-api/src/main/java/com/willfp/eco/core/config/wrapper/ConfigFactory.java

@@ -0,0 +1,81 @@
+package com.willfp.eco.core.config.wrapper;
+
+import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.PluginLike;
+import com.willfp.eco.core.config.ConfigType;
+import com.willfp.eco.core.config.interfaces.Config;
+import com.willfp.eco.core.config.interfaces.LoadableConfig;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Map;
+
+/**
+ * Internal component to create backend config implementations.
+ */
+@ApiStatus.Internal
+@Eco.HandlerComponent
+public interface ConfigFactory {
+    /**
+     * Updatable config.
+     *
+     * @param configName       The name of the config
+     * @param plugin           The plugin.
+     * @param subDirectoryPath The subdirectory path.
+     * @param source           The class that owns the resource.
+     * @param removeUnused     Whether keys not present in the default config should be removed on update.
+     * @param type             The config type.
+     * @param updateBlacklist  Substring of keys to not add/remove keys for.
+     * @return The config implementation.
+     */
+    LoadableConfig createUpdatableConfig(@NotNull String configName,
+                                         @NotNull PluginLike plugin,
+                                         @NotNull String subDirectoryPath,
+                                         @NotNull Class<?> source,
+                                         boolean removeUnused,
+                                         @NotNull ConfigType type,
+                                         @NotNull String... updateBlacklist);
+
+    /**
+     * Loadable config.
+     *
+     * @param configName       The name of the config
+     * @param plugin           The plugin.
+     * @param subDirectoryPath The subdirectory path.
+     * @param source           The class that owns the resource.
+     * @param type             The config type.
+     * @return The config implementation.
+     */
+    LoadableConfig createLoadableConfig(@NotNull String configName,
+                                        @NotNull PluginLike plugin,
+                                        @NotNull String subDirectoryPath,
+                                        @NotNull Class<?> source,
+                                        @NotNull ConfigType type);
+
+    /**
+     * Create config.
+     *
+     * @param config The handle.
+     * @return The config implementation.
+     */
+    Config createConfig(@NotNull YamlConfiguration config);
+
+    /**
+     * Create config.
+     *
+     * @param values The values.
+     * @return The config implementation.
+     */
+    Config createConfig(@NotNull Map<String, Object> values);
+
+    /**
+     * Create config.
+     *
+     * @param contents The file contents.
+     * @param type     The type.
+     * @return The config implementation.
+     */
+    Config createConfig(@NotNull String contents,
+                        @NotNull ConfigType type);
+}

eco-api/src/main/java/com/willfp/eco/core/config/wrapper/ConfigWrapper.java

@@ -0,0 +1,145 @@
+package com.willfp.eco.core.config.wrapper;
+
+import com.willfp.eco.core.config.ConfigType;
+import com.willfp.eco.core.config.interfaces.Config;
+import com.willfp.eco.util.StringUtils;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.List;
+
+/**
+ * Configs from eco have an internal implementation,
+ * which is the handle.
+ * <p>
+ * This class handles them.
+ *
+ * @param <T> The type of the handle.
+ */
+@SuppressWarnings("MethodDoesntCallSuperMethod")
+public abstract class ConfigWrapper<T extends Config> implements Config {
+    /**
+     * Configs from eco have an internal implementation,
+     * which is the handle.
+     * <p>
+     * The handle should only ever be used if you want to
+     * do something <i>interesting</i> config-wise with some
+     * internals.
+     * <p>
+     * In general use, though, the handle isn't necessary.
+     */
+    private final T handle;
+
+    /**
+     * Create a config wrapper.
+     *
+     * @param handle The config that is being wrapped.
+     */
+    protected ConfigWrapper(@NotNull final T handle) {
+        this.handle = handle;
+    }
+
+    @Override
+    public void clearCache() {
+        handle.clearCache();
+    }
+
+    @Override
+    public String toPlaintext() {
+        return handle.toPlaintext();
+    }
+
+    @Override
+    public boolean has(@NotNull final String path) {
+        return handle.has(path);
+    }
+
+    @Override
+    public @NotNull List<String> getKeys(final boolean deep) {
+        return handle.getKeys(deep);
+    }
+
+    @Override
+    public @Nullable Object get(@NotNull final String path) {
+        return handle.get(path);
+    }
+
+    @Override
+    public void set(@NotNull final String path,
+                    @Nullable final Object object) {
+        handle.set(path, object);
+    }
+
+    @Override
+    public @Nullable Config getSubsectionOrNull(@NotNull final String path) {
+        return handle.getSubsectionOrNull(path);
+    }
+
+    @Override
+    public @Nullable Integer getIntOrNull(@NotNull final String path) {
+        return handle.getIntOrNull(path);
+    }
+
+    @Override
+    public @Nullable List<Integer> getIntsOrNull(@NotNull final String path) {
+        return handle.getIntsOrNull(path);
+    }
+
+    @Override
+    public @Nullable Boolean getBoolOrNull(@NotNull final String path) {
+        return handle.getBoolOrNull(path);
+    }
+
+    @Override
+    public @Nullable List<Boolean> getBoolsOrNull(@NotNull final String path) {
+        return handle.getBoolsOrNull(path);
+    }
+
+    @Override
+    public @Nullable String getStringOrNull(@NotNull final String path,
+                                            final boolean format,
+                                            @NotNull final StringUtils.FormatOption option) {
+        return handle.getStringOrNull(path, format, option);
+    }
+
+    @Override
+    public @Nullable List<String> getStringsOrNull(@NotNull final String path,
+                                                   final boolean format,
+                                                   @NotNull final StringUtils.FormatOption option) {
+        return handle.getStringsOrNull(path, format, option);
+    }
+
+    @Override
+    public @Nullable Double getDoubleOrNull(@NotNull final String path) {
+        return handle.getDoubleOrNull(path);
+    }
+
+    @Override
+    public @Nullable List<Double> getDoublesOrNull(@NotNull final String path) {
+        return handle.getDoublesOrNull(path);
+    }
+
+    @Override
+    public @Nullable List<? extends Config> getSubsectionsOrNull(@NotNull final String path) {
+        return handle.getSubsectionsOrNull(path);
+    }
+
+    @Override
+    public Config clone() {
+        return handle.clone();
+    }
+
+    @Override
+    public @NotNull ConfigType getType() {
+        return handle.getType();
+    }
+
+    /**
+     * Get the handle.
+     *
+     * @return The handle.
+     */
+    public T getHandle() {
+        return this.handle;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/wrapper/LoadableConfigWrapper.java

@@ -0,0 +1,53 @@
+package com.willfp.eco.core.config.wrapper;
+
+import com.willfp.eco.core.config.interfaces.LoadableConfig;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.io.File;
+import java.io.IOException;
+
+/**
+ * Wrapper to handle the backend loadable yaml config implementations.
+ */
+public abstract class LoadableConfigWrapper extends ConfigWrapper<LoadableConfig> implements LoadableConfig {
+    /**
+     * Create a config wrapper.
+     *
+     * @param handle The handle.
+     */
+    protected LoadableConfigWrapper(@NotNull final LoadableConfig handle) {
+        super(handle);
+    }
+
+    @Override
+    public void createFile() {
+        this.getHandle().createFile();
+    }
+
+    @Override
+    public String getResourcePath() {
+        return this.getHandle().getResourcePath();
+    }
+
+    @Override
+    public void save() throws IOException {
+        this.getHandle().save();
+    }
+
+    @Override
+    public File getConfigFile() {
+        return this.getHandle().getConfigFile();
+    }
+
+    @Override
+    public String getName() {
+        return this.getHandle().getName();
+    }
+
+    @Override
+    public @Nullable YamlConfiguration getBukkitHandle() {
+        return this.getHandle().getBukkitHandle();
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/yaml/YamlBaseConfig.java

@@ -0,0 +1,87 @@
+package com.willfp.eco.core.config.yaml;
+
+import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.EcoPlugin;
+import com.willfp.eco.core.PluginLike;
+import com.willfp.eco.core.config.ConfigType;
+import com.willfp.eco.core.config.yaml.wrapper.LoadableYamlConfigWrapper;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Config implementation for configs present in the plugin's base directory (eg config.yml, lang.yml).
+ * <p>
+ * Automatically updates.
+ *
+ * @deprecated JSON and yml have full parity, use configs without a prefix instead,
+ * eg {@link com.willfp.eco.core.config.TransientConfig}, {@link com.willfp.eco.core.config.BaseConfig}.
+ * These configs will be removed eventually.
+ */
+@Deprecated(since = "6.17.0")
+public abstract class YamlBaseConfig extends LoadableYamlConfigWrapper {
+    /**
+     * @param configName      The name of the config
+     * @param removeUnused    Whether keys not present in the default config should be removed on update.
+     * @param plugin          The plugin.
+     * @param updateBlacklist Substring of keys to not add/remove keys for.
+     */
+    protected YamlBaseConfig(@NotNull final String configName,
+                             final boolean removeUnused,
+                             @NotNull final PluginLike plugin,
+                             @NotNull final String... updateBlacklist) {
+        super(
+                Eco.getHandler().getConfigFactory().createUpdatableConfig(
+                        configName,
+                        plugin,
+                        "",
+                        plugin.getClass(),
+                        removeUnused,
+                        ConfigType.YAML,
+                        updateBlacklist
+                )
+        );
+    }
+
+    /**
+     * @param configName   The name of the config
+     * @param removeUnused Whether keys not present in the default config should be removed on update.
+     * @param plugin       The plugin.
+     */
+    protected YamlBaseConfig(@NotNull final String configName,
+                             final boolean removeUnused,
+                             @NotNull final PluginLike plugin) {
+        super(
+                Eco.getHandler().getConfigFactory().createUpdatableConfig(
+                        configName,
+                        plugin,
+                        "",
+                        plugin.getClass(),
+                        removeUnused,
+                        ConfigType.YAML
+                )
+        );
+    }
+
+    /**
+     * @param configName      The name of the config
+     * @param removeUnused    Whether keys not present in the default config should be removed on update.
+     * @param plugin          The plugin.
+     * @param updateBlacklist Substring of keys to not add/remove keys for.
+     */
+    protected YamlBaseConfig(@NotNull final String configName,
+                             final boolean removeUnused,
+                             @NotNull final EcoPlugin plugin,
+                             @NotNull final String... updateBlacklist) {
+        this(configName, removeUnused, (PluginLike) plugin, updateBlacklist);
+    }
+
+    /**
+     * @param configName   The name of the config
+     * @param removeUnused Whether keys not present in the default config should be removed on update.
+     * @param plugin       The plugin.
+     */
+    protected YamlBaseConfig(@NotNull final String configName,
+                             final boolean removeUnused,
+                             @NotNull final EcoPlugin plugin) {
+        this(configName, removeUnused, (PluginLike) plugin);
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/yaml/YamlExtendableConfig.java

@@ -0,0 +1,68 @@
+package com.willfp.eco.core.config.yaml;
+
+import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.EcoPlugin;
+import com.willfp.eco.core.PluginLike;
+import com.willfp.eco.core.config.ConfigType;
+import com.willfp.eco.core.config.yaml.wrapper.LoadableYamlConfigWrapper;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Config implementation for configs present in one of two places:
+ * <ul>
+ *     <li>Plugin base directory (eg config.yml, lang.yml)</li>
+ *     <li>Other extension's configs</li>
+ * </ul>
+ * <p>
+ * Automatically updates.
+ *
+ * @deprecated JSON and yml have full parity, use configs without a prefix instead,
+ * eg {@link com.willfp.eco.core.config.TransientConfig}, {@link com.willfp.eco.core.config.BaseConfig}.
+ * These configs will be removed eventually.
+ */
+@Deprecated(since = "6.17.0")
+public abstract class YamlExtendableConfig extends LoadableYamlConfigWrapper {
+    /**
+     * @param configName       The name of the config
+     * @param removeUnused     Whether keys not present in the default config should be removed on update.
+     * @param plugin           The plugin.
+     * @param updateBlacklist  Substring of keys to not add/remove keys for.
+     * @param subDirectoryPath The subdirectory path.
+     * @param source           The class that owns the resource.
+     */
+    protected YamlExtendableConfig(@NotNull final String configName,
+                                   final boolean removeUnused,
+                                   @NotNull final PluginLike plugin,
+                                   @NotNull final Class<?> source,
+                                   @NotNull final String subDirectoryPath,
+                                   @NotNull final String... updateBlacklist) {
+        super(
+                Eco.getHandler().getConfigFactory().createUpdatableConfig(
+                        configName,
+                        plugin,
+                        subDirectoryPath,
+                        source,
+                        removeUnused,
+                        ConfigType.YAML,
+                        updateBlacklist
+                )
+        );
+    }
+
+    /**
+     * @param configName       The name of the config
+     * @param removeUnused     Whether keys not present in the default config should be removed on update.
+     * @param plugin           The plugin.
+     * @param updateBlacklist  Substring of keys to not add/remove keys for.
+     * @param subDirectoryPath The subdirectory path.
+     * @param source           The class that owns the resource.
+     */
+    protected YamlExtendableConfig(@NotNull final String configName,
+                                   final boolean removeUnused,
+                                   @NotNull final EcoPlugin plugin,
+                                   @NotNull final Class<?> source,
+                                   @NotNull final String subDirectoryPath,
+                                   @NotNull final String... updateBlacklist) {
+        this(configName, removeUnused, (PluginLike) plugin, source, subDirectoryPath, updateBlacklist);
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/yaml/YamlStaticBaseConfig.java

@@ -0,0 +1,44 @@
+package com.willfp.eco.core.config.yaml;
+
+import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.EcoPlugin;
+import com.willfp.eco.core.PluginLike;
+import com.willfp.eco.core.config.ConfigType;
+import com.willfp.eco.core.config.yaml.wrapper.LoadableYamlConfigWrapper;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Non-updatable yaml config that exists within a plugin jar.
+ *
+ * @deprecated JSON and yml have full parity, use configs without a prefix instead,
+ * eg {@link com.willfp.eco.core.config.TransientConfig}, {@link com.willfp.eco.core.config.BaseConfig}.
+ * These configs will be removed eventually.
+ */
+@Deprecated(since = "6.17.0")
+public abstract class YamlStaticBaseConfig extends LoadableYamlConfigWrapper {
+    /**
+     * Config implementation for configs present in the plugin's base directory (eg config.yml, lang.yml).
+     * <p>
+     * Does not automatically update.
+     *
+     * @param configName The name of the config
+     * @param plugin     The plugin.
+     */
+    protected YamlStaticBaseConfig(@NotNull final String configName,
+                                   @NotNull final PluginLike plugin) {
+        super(Eco.getHandler().getConfigFactory().createLoadableConfig(configName, plugin, "", plugin.getClass(), ConfigType.YAML));
+    }
+
+    /**
+     * Config implementation for configs present in the plugin's base directory (eg config.yml, lang.yml).
+     * <p>
+     * Does not automatically update.
+     *
+     * @param configName The name of the config
+     * @param plugin     The plugin.
+     */
+    protected YamlStaticBaseConfig(@NotNull final String configName,
+                                   @NotNull final EcoPlugin plugin) {
+        this(configName, (PluginLike) plugin);
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/yaml/YamlTransientConfig.java

@@ -0,0 +1,42 @@
+package com.willfp.eco.core.config.yaml;
+
+import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.config.ConfigType;
+import com.willfp.eco.core.config.yaml.wrapper.YamlConfigWrapper;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.jetbrains.annotations.NotNull;
+
+import java.io.StringReader;
+
+/**
+ * Config implementation for passing YamlConfigurations.
+ * <p>
+ * Does not automatically update.
+ *
+ * @deprecated JSON and yml have full parity, use configs without a prefix instead,
+ * eg {@link com.willfp.eco.core.config.TransientConfig}, {@link com.willfp.eco.core.config.BaseConfig}.
+ * These configs will be removed eventually.
+ */
+@Deprecated(since = "6.17.0")
+public class YamlTransientConfig extends YamlConfigWrapper {
+    /**
+     * @param config The YamlConfiguration handle.
+     */
+    public YamlTransientConfig(@NotNull final YamlConfiguration config) {
+        super(Eco.getHandler().getConfigFactory().createConfig(config));
+    }
+
+    /**
+     * @param contents The contents of the config.
+     */
+    public YamlTransientConfig(@NotNull final String contents) {
+        super(Eco.getHandler().getConfigFactory().createConfig(contents, ConfigType.YAML));
+    }
+
+    /**
+     * Create a new empty transient config.
+     */
+    public YamlTransientConfig() {
+        super(Eco.getHandler().getConfigFactory().createConfig(YamlConfiguration.loadConfiguration(new StringReader(""))));
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/yaml/wrapper/LoadableYamlConfigWrapper.java

@@ -0,0 +1,63 @@
+package com.willfp.eco.core.config.yaml.wrapper;
+
+import com.willfp.eco.core.config.interfaces.Config;
+import com.willfp.eco.core.config.interfaces.LoadableConfig;
+import org.apache.commons.lang.Validate;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.io.File;
+import java.io.IOException;
+
+/**
+ * Wrapper to handle the backend loadable yaml config implementations.
+ *
+ * @deprecated JSON and yml have full parity, use configs without a prefix instead,
+ * eg {@link com.willfp.eco.core.config.TransientConfig}, {@link com.willfp.eco.core.config.BaseConfig}.
+ * These configs will be removed eventually.
+ */
+@Deprecated(since = "6.17.0")
+public abstract class LoadableYamlConfigWrapper extends YamlConfigWrapper implements LoadableConfig {
+    /**
+     * Create a config wrapper.
+     *
+     * @param handle The handle.
+     */
+    protected LoadableYamlConfigWrapper(@NotNull final Config handle) {
+        super(handle);
+
+        Validate.isTrue(handle instanceof LoadableConfig, "Wrapped config must be loadable!");
+    }
+
+
+    @Override
+    public void createFile() {
+        ((LoadableConfig) this.getHandle()).createFile();
+    }
+
+    @Override
+    public String getResourcePath() {
+        return ((LoadableConfig) this.getHandle()).getResourcePath();
+    }
+
+    @Override
+    public void save() throws IOException {
+        ((LoadableConfig) this.getHandle()).save();
+    }
+
+    @Override
+    public File getConfigFile() {
+        return ((LoadableConfig) this.getHandle()).getConfigFile();
+    }
+
+    @Override
+    public String getName() {
+        return ((LoadableConfig) this.getHandle()).getName();
+    }
+
+    @Override
+    public @Nullable YamlConfiguration getBukkitHandle() {
+        return ((LoadableConfig) this.getHandle()).getBukkitHandle();
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/config/yaml/wrapper/YamlConfigWrapper.java

@@ -0,0 +1,31 @@
+package com.willfp.eco.core.config.yaml.wrapper;
+
+import com.willfp.eco.core.config.interfaces.Config;
+import com.willfp.eco.core.config.interfaces.WrappedYamlConfiguration;
+import com.willfp.eco.core.config.wrapper.ConfigWrapper;
+import org.bukkit.configuration.file.YamlConfiguration;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Wrapper to handle the backend yaml config implementations.
+ *
+ * @deprecated JSON and yml have full parity, use configs without a prefix instead,
+ * eg {@link com.willfp.eco.core.config.TransientConfig}, {@link com.willfp.eco.core.config.BaseConfig}.
+ * These configs will be removed eventually.
+ */
+@Deprecated(since = "6.17.0")
+public abstract class YamlConfigWrapper extends ConfigWrapper<Config> implements WrappedYamlConfiguration {
+    /**
+     * Create a config wrapper.
+     *
+     * @param handle The handle.
+     */
+    protected YamlConfigWrapper(@NotNull final Config handle) {
+        super(handle);
+    }
+
+    @Override
+    public YamlConfiguration getBukkitHandle() {
+        return ((WrappedYamlConfiguration) this.getHandle()).getBukkitHandle();
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/data/PlayerProfile.java

@@ -0,0 +1,36 @@
+package com.willfp.eco.core.data;
+
+import com.willfp.eco.core.Eco;
+import org.bukkit.OfflinePlayer;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.UUID;
+
+/**
+ * Persistent data storage interface for players.
+ * <p>
+ * Profiles save automatically, so there is no need to save after changes.
+ */
+public interface PlayerProfile extends Profile {
+    /**
+     * Load a player profile.
+     *
+     * @param player The player.
+     * @return The profile.
+     */
+    @NotNull
+    static PlayerProfile load(@NotNull final OfflinePlayer player) {
+        return load(player.getUniqueId());
+    }
+
+    /**
+     * Load a player profile.
+     *
+     * @param uuid The player's UUID.
+     * @return The profile.
+     */
+    @NotNull
+    static PlayerProfile load(@NotNull final UUID uuid) {
+        return Eco.getHandler().getProfileHandler().load(uuid);
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/data/Profile.java

@@ -0,0 +1,30 @@
+package com.willfp.eco.core.data;
+
+import com.willfp.eco.core.data.keys.PersistentDataKey;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Persistent data storage interface.
+ * <p>
+ * Profiles save automatically, so there is no need to save after changes.
+ */
+public interface Profile {
+    /**
+     * Write a key to persistent data.
+     *
+     * @param key   The key.
+     * @param value The value.
+     * @param <T>   The type of the key.
+     */
+    <T> void write(@NotNull PersistentDataKey<T> key,
+                   @NotNull T value);
+
+    /**
+     * Read a key from persistent data.
+     *
+     * @param key The key.
+     * @param <T> The type of the key.
+     * @return The value, or the default value if not found.
+     */
+    <T> @NotNull T read(@NotNull PersistentDataKey<T> key);
+}

eco-api/src/main/java/com/willfp/eco/core/data/ProfileHandler.java

@@ -0,0 +1,89 @@
+package com.willfp.eco.core.data;
+
+import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.data.keys.PersistentDataKey;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Set;
+import java.util.UUID;
+
+/**
+ * API to handle profiles.
+ */
+@ApiStatus.Internal
+@Eco.HandlerComponent
+public interface ProfileHandler {
+    /**
+     * Load a player profile.
+     *
+     * @param uuid The UUID.
+     * @return The profile.
+     */
+    PlayerProfile load(@NotNull UUID uuid);
+
+    /**
+     * Load the server profile.
+     *
+     * @return The profile.
+     */
+    ServerProfile loadServerProfile();
+
+    /**
+     * Unload a player profile from memory.
+     * <p>
+     * This will not save the profile first.
+     *
+     * @param uuid The uuid.
+     */
+    void unloadPlayer(@NotNull UUID uuid);
+
+    /**
+     * Save a player profile.
+     * <p>
+     * Can run async if using MySQL.
+     *
+     * @param uuid The uuid.
+     * @deprecated Saving changes is faster and should be used. Saving a player manually is not recommended.
+     */
+    @Deprecated
+    default void savePlayer(@NotNull UUID uuid) {
+        this.saveKeysFor(uuid, PersistentDataKey.values());
+    }
+
+    /**
+     * Save keys for a player.
+     * <p>
+     * Can run async if using MySQL.
+     *
+     * @param uuid The uuid.
+     * @param keys The keys.
+     */
+    void saveKeysFor(@NotNull UUID uuid,
+                     @NotNull Set<PersistentDataKey<?>> keys);
+
+    /**
+     * Save all player data.
+     *
+     * @param async If the saving should be done asynchronously.
+     * @deprecated async is now handled automatically depending on implementation.
+     */
+    @Deprecated
+    default void saveAll(boolean async) {
+        saveAll();
+    }
+
+    /**
+     * Save all player data.
+     * <p>
+     * Can run async if using MySQL.
+     */
+    void saveAll();
+
+    /**
+     * Commit all changes to the file.
+     * <p>
+     * Does nothing if using MySQL.
+     */
+    void save();
+}

eco-api/src/main/java/com/willfp/eco/core/data/ServerProfile.java

@@ -0,0 +1,21 @@
+package com.willfp.eco.core.data;
+
+import com.willfp.eco.core.Eco;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Persistent data storage interface for servers.
+ * <p>
+ * Profiles save automatically, so there is no need to save after changes.
+ */
+public interface ServerProfile extends Profile {
+    /**
+     * Load the server profile.
+     *
+     * @return The profile.
+     */
+    @NotNull
+    static ServerProfile load() {
+        return Eco.getHandler().getProfileHandler().loadServerProfile();
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/data/keys/KeyRegistry.java

@@ -0,0 +1,63 @@
+package com.willfp.eco.core.data.keys;
+
+import com.willfp.eco.core.Eco;
+import org.bukkit.NamespacedKey;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Set;
+
+/**
+ * API to register persistent data keys.
+ */
+@ApiStatus.Internal
+@Eco.HandlerComponent
+public interface KeyRegistry {
+    /**
+     * Register a persistent data key to be stored.
+     *
+     * @param key The key.
+     */
+    void registerKey(@NotNull PersistentDataKey<?> key);
+
+    /**
+     * Get all registered keys.
+     *
+     * @return The keys.
+     */
+    Set<PersistentDataKey<?>> getRegisteredKeys();
+
+    /**
+     * Mark key as category.
+     *
+     * @param key      The key.
+     * @param category The category.
+     */
+    void markKeyAs(@NotNull PersistentDataKey<?> key,
+                   @NotNull KeyRegistry.KeyCategory category);
+
+    /**
+     * Get persistent data key from namespaced key.
+     *
+     * @param namespacedKey The key.
+     * @return The key, or null if not found.
+     */
+    @Nullable
+    PersistentDataKey<?> getKeyFrom(@NotNull NamespacedKey namespacedKey);
+
+    /**
+     * Locations for key categorization.
+     */
+    enum KeyCategory {
+        /**
+         * Player keys.
+         */
+        PLAYER,
+
+        /**
+         * Server keys.
+         */
+        SERVER
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/data/keys/PersistentDataKey.java

@@ -0,0 +1,135 @@
+package com.willfp.eco.core.data.keys;
+
+import com.willfp.eco.core.Eco;
+import org.bukkit.NamespacedKey;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Objects;
+import java.util.Set;
+
+/**
+ * A persistent data key is a key with a type that can be stored about an offline player.
+ *
+ * @param <T> The type of the data.
+ */
+public final class PersistentDataKey<T> {
+    /**
+     * The key of the persistent data value.
+     */
+    private final NamespacedKey key;
+
+    /**
+     * The default value for the key.
+     */
+    private final T defaultValue;
+
+    /**
+     * The persistent data key type.
+     */
+    private final PersistentDataKeyType<T> type;
+
+    /**
+     * Create a new Persistent Data Key.
+     *
+     * @param key          The key.
+     * @param type         The data type.
+     * @param defaultValue The default value.
+     */
+    public PersistentDataKey(@NotNull final NamespacedKey key,
+                             @NotNull final PersistentDataKeyType<T> type,
+                             @NotNull final T defaultValue) {
+        this.key = key;
+        this.defaultValue = defaultValue;
+        this.type = type;
+
+        Eco.getHandler().getKeyRegistry().registerKey(this);
+    }
+
+    @Override
+    public String toString() {
+        return "PersistentDataKey{"
+                + "key=" + key
+                + ", defaultValue=" + defaultValue
+                + ", type=" + type
+                + '}';
+    }
+
+    /**
+     * Get the key.
+     *
+     * @return The key.
+     */
+    public NamespacedKey getKey() {
+        return this.key;
+    }
+
+    /**
+     * Get the default value.
+     *
+     * @return The default value.
+     */
+    public T getDefaultValue() {
+        return this.defaultValue;
+    }
+
+    /**
+     * Get the data key type.
+     *
+     * @return The key type.
+     */
+    public PersistentDataKeyType<T> getType() {
+        return this.type;
+    }
+
+    /**
+     * Categorize key as a server key, will register new column to MySQL
+     * database immediately rather than waiting for auto-categorization.
+     * <p>
+     * This will improve performance.
+     *
+     * @return The key.
+     */
+    public PersistentDataKey<T> server() {
+        Eco.getHandler().getKeyRegistry().markKeyAs(this, KeyRegistry.KeyCategory.SERVER);
+        return this;
+    }
+
+    /**
+     * Categorize key as a player key, will register new column to MySQL
+     * database immediately rather than waiting for auto-categorization.
+     * <p>
+     * This will improve performance.
+     *
+     * @return The key.
+     */
+    public PersistentDataKey<T> player() {
+        Eco.getHandler().getKeyRegistry().markKeyAs(this, KeyRegistry.KeyCategory.PLAYER);
+        return this;
+    }
+
+    /**
+     * Get all persistent data keys.
+     *
+     * @return The keys.
+     */
+    public static Set<PersistentDataKey<?>> values() {
+        return Eco.getHandler().getKeyRegistry().getRegisteredKeys();
+    }
+
+    @Override
+    public boolean equals(@Nullable final Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (!(o instanceof PersistentDataKey that)) {
+            return false;
+        }
+        return Objects.equals(this.getKey(), that.getKey());
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(this.getKey());
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/data/keys/PersistentDataKeyType.java

@@ -0,0 +1,108 @@
+package com.willfp.eco.core.data.keys;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * All storable data key types.
+ *
+ * @param <T> The type.
+ */
+public final class PersistentDataKeyType<T> {
+    /**
+     * The registered key types.
+     */
+    private static final List<PersistentDataKeyType<?>> VALUES = new ArrayList<>();
+
+    /**
+     * String.
+     */
+    public static final PersistentDataKeyType<String> STRING = new PersistentDataKeyType<>(String.class, "STRING");
+
+    /**
+     * Boolean.
+     */
+    public static final PersistentDataKeyType<Boolean> BOOLEAN = new PersistentDataKeyType<>(Boolean.class, "BOOLEAN");
+
+    /**
+     * Int.
+     */
+    public static final PersistentDataKeyType<Integer> INT = new PersistentDataKeyType<>(Integer.class, "INT");
+
+    /**
+     * Double.
+     */
+    public static final PersistentDataKeyType<Double> DOUBLE = new PersistentDataKeyType<>(Double.class, "DOUBLE");
+
+    /**
+     * The class of the type.
+     */
+    private final Class<T> typeClass;
+
+    /**
+     * The name of the key type.
+     */
+    private final String name;
+
+    /**
+     * Get the class of the type.
+     *
+     * @return The class.
+     */
+    public Class<T> getTypeClass() {
+        return typeClass;
+    }
+
+    /**
+     * Get the name of the key type.
+     *
+     * @return The name.
+     */
+    public String name() {
+        return name;
+    }
+
+    /**
+     * Create new PersistentDataKeyType.
+     *
+     * @param typeClass The type class.
+     * @param name      The name.
+     */
+    private PersistentDataKeyType(@NotNull final Class<T> typeClass,
+                                  @NotNull final String name) {
+        VALUES.add(this);
+
+        this.typeClass = typeClass;
+        this.name = name;
+    }
+
+    /**
+     * Get all registered {@link PersistentDataKeyType}s.
+     *
+     * @return The registered types.
+     */
+    @NotNull
+    public static PersistentDataKeyType<?>[] values() {
+        return VALUES.toArray(new PersistentDataKeyType[0]);
+    }
+
+    /**
+     * Get a key type from a name.
+     *
+     * @param name The name.
+     * @return The type, or null if not found.
+     */
+    @Nullable
+    public static PersistentDataKeyType<?> valueOf(@NotNull final String name) {
+        for (PersistentDataKeyType<?> type : VALUES) {
+            if (type.name.equalsIgnoreCase(name)) {
+                return type;
+            }
+        }
+
+        return null;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/display/Display.java

@@ -0,0 +1,181 @@
+package com.willfp.eco.core.display;
+
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Utility class to manage client-side item display.
+ */
+public final class Display {
+    /**
+     * The prefix for client-side lore lines.
+     */
+    public static final String PREFIX = "§z";
+
+    /**
+     * The display handler.
+     */
+    private static DisplayHandler handler = null;
+
+    /**
+     * Display on ItemStacks.
+     *
+     * @param itemStack The item.
+     * @return The ItemStack.
+     */
+    public static ItemStack display(@NotNull final ItemStack itemStack) {
+        return display(itemStack, null);
+    }
+
+    /**
+     * Display on ItemStacks.
+     *
+     * @param itemStack The item.
+     * @param player    The player.
+     * @return The ItemStack.
+     */
+    public static ItemStack display(@NotNull final ItemStack itemStack,
+                                    @Nullable final Player player) {
+        return handler.display(itemStack, player);
+    }
+
+    /**
+     * Display on ItemStacks and then finalize.
+     *
+     * @param itemStack The item.
+     * @return The ItemStack.
+     */
+    public static ItemStack displayAndFinalize(@NotNull final ItemStack itemStack) {
+        return finalize(display(itemStack, null));
+    }
+
+    /**
+     * Display on ItemStacks and then finalize.
+     *
+     * @param itemStack The item.
+     * @param player    The player.
+     * @return The ItemStack.
+     */
+    public static ItemStack displayAndFinalize(@NotNull final ItemStack itemStack,
+                                               @Nullable final Player player) {
+        return finalize(display(itemStack, player));
+    }
+
+    /**
+     * Revert on ItemStacks.
+     *
+     * @param itemStack The item.
+     * @return The ItemStack.
+     */
+    public static ItemStack revert(@NotNull final ItemStack itemStack) {
+        return handler.revert(itemStack);
+    }
+
+    /**
+     * Finalize an ItemStacks.
+     *
+     * @param itemStack The item.
+     * @return The ItemStack.
+     */
+    public static ItemStack finalize(@NotNull final ItemStack itemStack) {
+        return handler.finalize(itemStack);
+    }
+
+    /**
+     * Unfinalize an ItemStacks.
+     *
+     * @param itemStack The item.
+     * @return The ItemStack.
+     */
+    public static ItemStack unfinalize(@NotNull final ItemStack itemStack) {
+        return handler.unfinalize(itemStack);
+    }
+
+    /**
+     * If an item is finalized.
+     *
+     * @param itemStack The item.
+     * @return If finalized.
+     */
+    public static boolean isFinalized(@NotNull final ItemStack itemStack) {
+        return handler.isFinalized(itemStack);
+    }
+
+    /**
+     * Register a new display module.
+     *
+     * @param module The module.
+     */
+    public static void registerDisplayModule(@NotNull final DisplayModule module) {
+        handler.registerDisplayModule(module);
+    }
+
+    /**
+     * Initialize the display system.
+     *
+     * @param handler The handler.
+     */
+    @ApiStatus.Internal
+    public static void init(@NotNull final DisplayHandler handler) {
+        if (Display.handler != null) {
+            throw new IllegalArgumentException("Already Initialized!");
+        }
+        Display.handler = handler;
+    }
+
+    /**
+     * Extremely janky method - also internal, so don't use it. <b>This method is
+     * NOT part of the API and may be removed at any time!</b>
+     * <p>
+     * This calls a display module with the specified parameters, now
+     * you might ask why I need a static java method when the DisplayHandler
+     * implementation could just call it itself? Well, kotlin doesn't really
+     * like dealing with vararg ambiguity, and so while kotlin can't figure out
+     * what is and isn't a vararg when I call display with a player, java can.
+     * <p>
+     * Because of this, I need to have this part of the code in java.
+     *
+     * <b>Don't call this method as part of your plugins!</b>
+     * <p>
+     * No, seriously - don't. This skips a bunch of checks and you'll almost
+     * definitely break something.
+     *
+     * @param module    The display module.
+     * @param itemStack The ItemStack.
+     * @param player    The player.
+     * @param args      The args.
+     */
+    @ApiStatus.Internal
+    public static void callDisplayModule(@NotNull final DisplayModule module,
+                                         @NotNull final ItemStack itemStack,
+                                         @Nullable final Player player,
+                                         @NotNull final Object... args) {
+        module.display(itemStack, args);
+        if (player != null) {
+            module.display(itemStack, player, args);
+        }
+    }
+
+    /**
+     * Set the display handler.
+     * <p>
+     * Internal API component, you will cause bugs if you create your own handler.
+     *
+     * @param handler The handler.
+     */
+    @ApiStatus.Internal
+    public static void setHandler(@NotNull final DisplayHandler handler) {
+        if (Display.handler != null) {
+            throw new IllegalStateException("Display already initialized!");
+        }
+
+        Display.handler = handler;
+    }
+
+    private Display() {
+        throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/display/DisplayHandler.java

@@ -0,0 +1,64 @@
+package com.willfp.eco.core.display;
+
+import com.willfp.eco.core.Eco;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Interface for display implementations.
+ */
+@ApiStatus.Internal
+@Eco.HandlerComponent
+public interface DisplayHandler {
+    /**
+     * Register display module.
+     *
+     * @param module The module.
+     */
+    void registerDisplayModule(@NotNull DisplayModule module);
+
+    /**
+     * Display on ItemStacks.
+     *
+     * @param itemStack The item.
+     * @param player    The player.
+     * @return The ItemStack.
+     */
+    ItemStack display(@NotNull ItemStack itemStack,
+                      @Nullable Player player);
+
+    /**
+     * Revert on ItemStacks.
+     *
+     * @param itemStack The item.
+     * @return The ItemStack.
+     */
+    ItemStack revert(@NotNull ItemStack itemStack);
+
+    /**
+     * Finalize an ItemStacks.
+     *
+     * @param itemStack The item.
+     * @return The ItemStack.
+     */
+    ItemStack finalize(@NotNull ItemStack itemStack);
+
+    /**
+     * Unfinalize an ItemStacks.
+     *
+     * @param itemStack The item.
+     * @return The ItemStack.
+     */
+    ItemStack unfinalize(@NotNull ItemStack itemStack);
+
+    /**
+     * If an item is finalized.
+     *
+     * @param itemStack The item.
+     * @return If finalized.
+     */
+    boolean isFinalized(@NotNull ItemStack itemStack);
+}

eco-api/src/main/java/com/willfp/eco/core/display/DisplayModule.java

@@ -0,0 +1,91 @@
+package com.willfp.eco.core.display;
+
+import com.willfp.eco.core.EcoPlugin;
+import com.willfp.eco.core.PluginDependent;
+import org.bukkit.entity.Player;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Class for all plugin-specific client-side item display modules.
+ */
+public abstract class DisplayModule extends PluginDependent<EcoPlugin> {
+    /**
+     * The priority of the module.
+     */
+    private final DisplayPriority priority;
+
+    /**
+     * Create a new display module.
+     *
+     * @param plugin   The plugin that the display is for.
+     * @param priority The priority of the module.
+     */
+    protected DisplayModule(@NotNull final EcoPlugin plugin,
+                            @NotNull final DisplayPriority priority) {
+        super(plugin);
+        this.priority = priority;
+    }
+
+    /**
+     * Display an item.
+     *
+     * @param itemStack The item.
+     * @param args      Optional args for display.
+     */
+    public void display(@NotNull final ItemStack itemStack,
+                        @NotNull final Object... args) {
+        // Technically optional.
+    }
+
+    /**
+     * Display an item.
+     *
+     * @param itemStack The item.
+     * @param player    The player.
+     * @param args      Optional args for display.
+     */
+    public void display(@NotNull final ItemStack itemStack,
+                        @Nullable final Player player,
+                        @NotNull final Object... args) {
+        // Technically optional.
+    }
+
+    /**
+     * Revert an item.
+     *
+     * @param itemStack The item.
+     */
+    public void revert(@NotNull final ItemStack itemStack) {
+        // Technically optional.
+    }
+
+    /**
+     * Create varargs to pass back to ItemStack after reverting, but before display.
+     *
+     * @param itemStack The itemStack.
+     * @return The plugin-specific varargs.
+     */
+    public Object[] generateVarArgs(@NotNull final ItemStack itemStack) {
+        return new Object[0];
+    }
+
+    /**
+     * Get name of plugin.
+     *
+     * @return The plugin name.
+     */
+    public final String getPluginName() {
+        return super.getPlugin().getName();
+    }
+
+    /**
+     * Get the display priority.
+     *
+     * @return The priority.
+     */
+    public DisplayPriority getPriority() {
+        return this.priority;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/display/DisplayPriority.java

@@ -0,0 +1,26 @@
+package com.willfp.eco.core.display;
+
+/**
+ * The priority (order) of display modules.
+ */
+public enum DisplayPriority {
+    /**
+     * Ran first.
+     */
+    LOWEST,
+
+    /**
+     * Ran second.
+     */
+    LOW,
+
+    /**
+     * Ran third.
+     */
+    HIGH,
+
+    /**
+     * Ran last.
+     */
+    HIGHEST
+}

eco-api/src/main/java/com/willfp/eco/core/drops/DropQueue.java

@@ -1,10 +1,6 @@
-package com.willfp.eco.util.drops;
+package com.willfp.eco.core.drops;
 
-import com.willfp.eco.util.drops.internal.AbstractDropQueue;
+import com.willfp.eco.core.Eco;
-import com.willfp.eco.util.drops.internal.DropManager;
-import com.willfp.eco.util.drops.internal.DropQueueType;
-import com.willfp.eco.util.drops.internal.FastCollatedDropQueue;
-import com.willfp.eco.util.drops.internal.InternalDropQueue;
 import org.bukkit.Location;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
@@ -12,21 +8,26 @@ import org.jetbrains.annotations.NotNull;
 
 import java.util.Collection;
 
+/**
+ * A {@link DropQueue} is a set of drops linked to player.
+ * <p>
+ * All drops should be passed through a drop queue for telekinesis integration.
+ * <p>
+ * It functions essentially as a builder class, and runs very quickly.
+ *
+ * @see com.willfp.eco.util.TelekinesisUtils
+ */
 public class DropQueue {
     /**
-     * The internally used {@link AbstractDropQueue}.
+     * The internally used {@link DropQueue}.
      */
-    private final AbstractDropQueue handle;
+    private final InternalDropQueue handle;
 
     /**
-     * Create {@link DropQueue} linked to player.
-     * <p>
-     * All drops should be passed through a drop queue for telekinesis integration.
-     *
      * @param player The player.
      */
     public DropQueue(@NotNull final Player player) {
-        handle = DropManager.getType() == DropQueueType.COLLATED ? new FastCollatedDropQueue(player) : new InternalDropQueue(player);
+        handle = Eco.getHandler().getDropQueueFactory().create(player);
     }
 
     /**

eco-api/src/main/java/com/willfp/eco/core/drops/DropQueueFactory.java

@@ -0,0 +1,21 @@
+package com.willfp.eco.core.drops;
+
+import com.willfp.eco.core.Eco;
+import org.bukkit.entity.Player;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Internal component to create backend DropQueue implementations.
+ */
+@ApiStatus.Internal
+@Eco.HandlerComponent
+public interface DropQueueFactory {
+    /**
+     * Create a DropQueue.
+     *
+     * @param player The player.
+     * @return The Queue.
+     */
+    InternalDropQueue create(@NotNull Player player);
+}

eco-api/src/main/java/com/willfp/eco/core/drops/InternalDropQueue.java

@@ -1,19 +1,26 @@
-package com.willfp.eco.util.drops.internal;
+package com.willfp.eco.core.drops;
 
+import com.willfp.eco.core.Eco;
 import org.bukkit.Location;
 import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.Collection;
 
-public interface AbstractDropQueue {
+/**
+ * Internal interface for backend DropQueue implementations.
+ */
+@ApiStatus.Internal
+@Eco.HandlerComponent
+public interface InternalDropQueue {
     /**
      * Add item to queue.
      *
      * @param item The item to add.
      * @return The DropQueue.
      */
-    AbstractDropQueue addItem(@NotNull ItemStack item);
+    InternalDropQueue addItem(@NotNull ItemStack item);
 
     /**
      * Add multiple items to queue.
@@ -21,7 +28,7 @@ public interface AbstractDropQueue {
      * @param itemStacks The items to add.
      * @return The DropQueue.
      */
-    AbstractDropQueue addItems(@NotNull Collection<ItemStack> itemStacks);
+    InternalDropQueue addItems(@NotNull Collection<ItemStack> itemStacks);
 
     /**
      * Add xp to queue.
@@ -29,7 +36,7 @@ public interface AbstractDropQueue {
      * @param amount The amount to add.
      * @return The DropQueue.
      */
-    AbstractDropQueue addXP(int amount);
+    InternalDropQueue addXP(int amount);
 
     /**
      * Set location of the origin of the drops.
@@ -37,14 +44,14 @@ public interface AbstractDropQueue {
      * @param location The location.
      * @return The DropQueue.
      */
-    AbstractDropQueue setLocation(@NotNull Location location);
+    InternalDropQueue setLocation(@NotNull Location location);
 
     /**
      * Force the queue to act as if player is telekinetic.
      *
      * @return The DropQueue.
      */
-    AbstractDropQueue forceTelekinesis();
+    InternalDropQueue forceTelekinesis();
 
     /**
      * Push the queue.

eco-api/src/main/java/com/willfp/eco/core/entities/CustomEntity.java

@@ -0,0 +1,84 @@
+package com.willfp.eco.core.entities;
+
+import org.apache.commons.lang.Validate;
+import org.bukkit.Location;
+import org.bukkit.NamespacedKey;
+import org.bukkit.entity.Entity;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.function.Function;
+import java.util.function.Predicate;
+
+/**
+ * A custom entity has 3 components.
+ *
+ * <ul>
+ *     <li>The key to identify it</li>
+ *     <li>The test to check if any entity is this custom entity</li>
+ *     <li>The supplier to spawn the custom {@link org.bukkit.entity.Entity}</li>
+ * </ul>
+ */
+public class CustomEntity implements TestableEntity {
+    /**
+     * The key.
+     */
+    private final NamespacedKey key;
+
+    /**
+     * The test for Entities to pass.
+     */
+    private final Predicate<@NotNull Entity> test;
+
+    /**
+     * The provider to spawn the entity.
+     */
+    private final Function<Location, Entity> provider;
+
+    /**
+     * Create a new custom entity.
+     *
+     * @param key      The entity key.
+     * @param test     The test.
+     * @param provider The provider to spawn the entity.
+     */
+    public CustomEntity(@NotNull final NamespacedKey key,
+                        @NotNull final Predicate<@NotNull Entity> test,
+                        @NotNull final Function<Location, Entity> provider) {
+        this.key = key;
+        this.test = test;
+        this.provider = provider;
+    }
+
+    @Override
+    public boolean matches(@Nullable final Entity entity) {
+        if (entity == null) {
+            return false;
+        }
+
+        return test.test(entity);
+    }
+
+    @Override
+    public Entity spawn(@NotNull final Location location) {
+        Validate.notNull(location.getWorld());
+
+        return provider.apply(location);
+    }
+
+    /**
+     * Register the entity.
+     */
+    public void register() {
+        Entities.registerCustomEntity(this.getKey(), this);
+    }
+
+    /**
+     * Get the key.
+     *
+     * @return The key.
+     */
+    public NamespacedKey getKey() {
+        return this.key;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/entities/DummyEntity.java

@@ -0,0 +1,10 @@
+package com.willfp.eco.core.entities;
+
+import org.bukkit.entity.Entity;
+
+/**
+ * Interface for Dummy Entities in order to filter them using instanceof.
+ */
+public interface DummyEntity extends Entity {
+
+}

eco-api/src/main/java/com/willfp/eco/core/entities/Entities.java

@@ -0,0 +1,232 @@
+package com.willfp.eco.core.entities;
+
+import com.willfp.eco.core.entities.args.EntityArgParseResult;
+import com.willfp.eco.core.entities.args.EntityArgParser;
+import com.willfp.eco.core.entities.impl.EmptyTestableEntity;
+import com.willfp.eco.core.entities.impl.ModifiedTestableEntity;
+import com.willfp.eco.core.entities.impl.SimpleTestableEntity;
+import com.willfp.eco.util.NamespacedKeyUtils;
+import org.bukkit.Location;
+import org.bukkit.NamespacedKey;
+import org.bukkit.entity.Entity;
+import org.bukkit.entity.EntityType;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Function;
+
+/**
+ * Class to manage all custom and vanilla entities.
+ */
+public final class Entities {
+    /**
+     * All entities.
+     */
+    private static final Map<NamespacedKey, TestableEntity> REGISTRY = new ConcurrentHashMap<>();
+
+    /**
+     * All entity parsers.
+     */
+    private static final List<EntityArgParser> ARG_PARSERS = new ArrayList<>();
+
+    /**
+     * The lookup handler.
+     */
+    private static final EntitiesLookupHandler ENTITIES_LOOKUP_HANDLER = new EntitiesLookupHandler(Entities::doParse);
+
+    /**
+     * Register a new custom item.
+     *
+     * @param key  The key of the item.
+     * @param item The item.
+     */
+    public static void registerCustomEntity(@NotNull final NamespacedKey key,
+                                            @NotNull final TestableEntity item) {
+        REGISTRY.put(key, item);
+    }
+
+    /**
+     * Register a new arg parser.
+     *
+     * @param parser The parser.
+     */
+    public static void registerArgParser(@NotNull final EntityArgParser parser) {
+        ARG_PARSERS.add(parser);
+    }
+
+    /**
+     * Remove an entity.
+     *
+     * @param key The key of the entity.
+     */
+    public static void removeCustomEntity(@NotNull final NamespacedKey key) {
+        REGISTRY.remove(key);
+    }
+
+    /**
+     * This is the backbone of the entire eco entity system.
+     * <p>
+     * You can look up a TestableEntity for any type or custom entity,
+     * and it will return it with any modifiers passed as parameters.
+     * <p>
+     * If you want to get an Entity instance from this, then just call
+     * {@link TestableEntity#spawn(Location)}.
+     * <p>
+     * The advantages of the testable entity system are that there is the inbuilt
+     * {@link TestableEntity#matches(Entity)} - this allows to check if any entity
+     * is that testable entity; which may sound negligible, but actually it allows for
+     * much more power and flexibility. For example, you can have an entity with an
+     * extra metadata tag, extra lore lines, different display name - and it
+     * will still work as long as the test passes.
+     *
+     * @param key The lookup string.
+     * @return The testable entity, or an empty testable entity if not found.
+     */
+    @NotNull
+    public static TestableEntity lookup(@NotNull final String key) {
+        return ENTITIES_LOOKUP_HANDLER.parseKey(key);
+    }
+
+    @NotNull
+    private static TestableEntity doParse(@NotNull final String[] args) {
+        if (args.length == 0) {
+            return new EmptyTestableEntity();
+        }
+
+        TestableEntity entity;
+
+        String[] split = args[0].toLowerCase().split(":");
+
+        if (split.length == 1) {
+            EntityType type;
+            try {
+                type = EntityType.valueOf(args[0].toUpperCase());
+            } catch (IllegalArgumentException e) {
+                return new EmptyTestableEntity();
+            }
+            entity = new SimpleTestableEntity(type);
+        } else {
+            String namespace = split[0];
+            String keyID = split[1];
+            NamespacedKey namespacedKey = NamespacedKeyUtils.create(namespace, keyID);
+
+            TestableEntity part = REGISTRY.get(namespacedKey);
+
+            if (part == null) {
+                return new EmptyTestableEntity();
+            }
+
+            entity = part;
+        }
+
+        String[] modifierArgs = Arrays.copyOfRange(args, 1, args.length);
+
+        List<EntityArgParseResult> parseResults = new ArrayList<>();
+
+        for (EntityArgParser argParser : ARG_PARSERS) {
+            EntityArgParseResult result = argParser.parseArguments(modifierArgs);
+            if (result != null) {
+                parseResults.add(result);
+            }
+        }
+
+        Function<Location, Entity> spawner = entity::spawn;
+
+        if (!parseResults.isEmpty()) {
+            entity = new ModifiedTestableEntity(
+                    entity,
+                    test -> {
+                        for (EntityArgParseResult parseResult : parseResults) {
+                            if (!parseResult.test().test(test)) {
+                                return false;
+                            }
+                        }
+
+                        return true;
+                    },
+                    location -> {
+                        Entity spawned = spawner.apply(location);
+
+                        for (EntityArgParseResult parseResult : parseResults) {
+                            parseResult.modifier().accept(spawned);
+                        }
+
+                        return spawned;
+                    }
+            );
+        }
+
+        return entity;
+    }
+
+    /**
+     * Get a Testable Entity from an ItemStack.
+     * <p>
+     * Will search for registered entity first. If there are no matches in the registry,
+     * then it will return a {@link com.willfp.eco.core.entities.impl.SimpleTestableEntity} matching the entity type.
+     * <p>
+     * If the entity is not custom and has unknown type, this will return null.
+     *
+     * @param entity The Entity.
+     * @return The found Testable Entity.
+     */
+    @Nullable
+    public static TestableEntity getEntity(@Nullable final Entity entity) {
+        if (entity == null) {
+            return null;
+        }
+
+        TestableEntity customEntity = getEntity(entity);
+
+        if (customEntity != null) {
+            return customEntity;
+        }
+
+        for (TestableEntity known : REGISTRY.values()) {
+            if (known.matches(entity)) {
+                return known;
+            }
+        }
+
+        if (entity.getType() == EntityType.UNKNOWN) {
+            return null;
+        }
+
+        return new SimpleTestableEntity(entity.getType());
+    }
+
+    /**
+     * Get if entity is a custom entity.
+     *
+     * @param entity The entity to check.
+     * @return If is custom.
+     */
+    public static boolean isCustomEntity(@NotNull final Entity entity) {
+        for (TestableEntity testable : REGISTRY.values()) {
+            if (testable.matches(entity)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Get all registered custom items.
+     *
+     * @return A set of all items.
+     */
+    public static Set<TestableEntity> getCustomEntities() {
+        return new HashSet<>(REGISTRY.values());
+    }
+
+    private Entities() {
+        throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/entities/EntitiesLookupHandler.java

@@ -0,0 +1,48 @@
+package com.willfp.eco.core.entities;
+
+import com.willfp.eco.core.entities.impl.EmptyTestableEntity;
+import com.willfp.eco.core.entities.impl.GroupedTestableEntities;
+import com.willfp.eco.core.lookup.LookupHandler;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collection;
+import java.util.function.Function;
+
+/**
+ * Handle item lookup strings.
+ */
+public class EntitiesLookupHandler implements LookupHandler<TestableEntity> {
+    /**
+     * The parser.
+     */
+    private final Function<String[], @NotNull TestableEntity> parser;
+
+    /**
+     * Create new lookup handler.
+     *
+     * @param parser The parser.
+     */
+    public EntitiesLookupHandler(@NotNull final Function<String[], @NotNull TestableEntity> parser) {
+        this.parser = parser;
+    }
+
+    @Override
+    public @NotNull TestableEntity parse(@NotNull final String[] args) {
+        return parser.apply(args);
+    }
+
+    @Override
+    public boolean validate(@NotNull final TestableEntity object) {
+        return !(object instanceof EmptyTestableEntity);
+    }
+
+    @Override
+    public @NotNull TestableEntity getFailsafe() {
+        return new EmptyTestableEntity();
+    }
+
+    @Override
+    public @NotNull TestableEntity join(@NotNull final Collection<TestableEntity> options) {
+        return new GroupedTestableEntities(options);
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/entities/TestableEntity.java

@@ -0,0 +1,29 @@
+package com.willfp.eco.core.entities;
+
+import com.willfp.eco.core.lookup.Testable;
+import org.bukkit.Location;
+import org.bukkit.entity.Entity;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * An item with a test to see if any item is that item.
+ */
+public interface TestableEntity extends Testable<Entity> {
+    /**
+     * If an Entity matches the test.
+     *
+     * @param entity The entity to test.
+     * @return If the entity matches.
+     */
+    @Override
+    boolean matches(@Nullable Entity entity);
+
+    /**
+     * Spawn the entity.
+     *
+     * @param location The location.
+     * @return The entity.
+     */
+    Entity spawn(@NotNull Location location);
+}

eco-api/src/main/java/com/willfp/eco/core/entities/args/EntityArgParseResult.java

@@ -0,0 +1,33 @@
+package com.willfp.eco.core.entities.args;
+
+import org.bukkit.entity.Entity;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.function.Consumer;
+import java.util.function.Predicate;
+
+/**
+ * @param test     The test for the entity.
+ * @param modifier The modifier to apply to the entity.
+ * @see EntityArgParser
+ */
+public record EntityArgParseResult(@NotNull Predicate<Entity> test,
+                                   @NotNull Consumer<Entity> modifier) {
+    /**
+     * Kotlin destructuring support.
+     *
+     * @return The test.
+     */
+    public Predicate<Entity> component1() {
+        return test;
+    }
+
+    /**
+     * Kotlin destructuring support.
+     *
+     * @return The modifier.
+     */
+    public Consumer<Entity> component2() {
+        return modifier;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/entities/args/EntityArgParser.java

@@ -0,0 +1,20 @@
+package com.willfp.eco.core.entities.args;
+
+import com.willfp.eco.core.entities.TestableEntity;
+import org.bukkit.Location;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * An argument parser should generate the predicate as well
+ * as modify the Entity for {@link TestableEntity#spawn(Location)}.
+ */
+public interface EntityArgParser {
+    /**
+     * Parse the arguments.
+     *
+     * @param args The arguments.
+     * @return The predicate test to apply to the modified entity.
+     */
+    @Nullable EntityArgParseResult parseArguments(@NotNull String[] args);
+}

eco-api/src/main/java/com/willfp/eco/core/entities/impl/EmptyTestableEntity.java

@@ -0,0 +1,33 @@
+package com.willfp.eco.core.entities.impl;
+
+import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.entities.TestableEntity;
+import org.apache.commons.lang.Validate;
+import org.bukkit.Location;
+import org.bukkit.entity.Entity;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Empty entity.
+ */
+public class EmptyTestableEntity implements TestableEntity {
+    /**
+     * Create a new empty testable entity.
+     */
+    public EmptyTestableEntity() {
+
+    }
+
+    @Override
+    public boolean matches(@Nullable final Entity entity) {
+        return false;
+    }
+
+    @Override
+    public Entity spawn(@NotNull final Location location) {
+        Validate.notNull(location.getWorld());
+
+        return Eco.getHandler().createDummyEntity(location);
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/entities/impl/GroupedTestableEntities.java

@@ -0,0 +1,68 @@
+package com.willfp.eco.core.entities.impl;
+
+import com.willfp.eco.core.entities.TestableEntity;
+import com.willfp.eco.util.NumberUtils;
+import org.apache.commons.lang.Validate;
+import org.bukkit.Location;
+import org.bukkit.entity.Entity;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.ArrayList;
+import java.util.Collection;
+
+/**
+ * A group of testable entities.
+ *
+ * @see com.willfp.eco.core.entities.CustomEntity
+ */
+public class GroupedTestableEntities implements TestableEntity {
+    /**
+     * The children.
+     */
+    private final Collection<TestableEntity> children;
+
+    /**
+     * Create a new group of testable entities.
+     *
+     * @param children The children.
+     */
+    public GroupedTestableEntities(@NotNull final Collection<TestableEntity> children) {
+        Validate.isTrue(!children.isEmpty(), "Group must have at least one child!");
+
+        this.children = children;
+    }
+
+    /**
+     * If the item matches any children.
+     *
+     * @param entity The entity to test.
+     * @return If the entity matches the test of any children.
+     */
+    @Override
+    public boolean matches(@Nullable final Entity entity) {
+        for (TestableEntity child : children) {
+            if (child.matches(entity)) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    @Override
+    public Entity spawn(@NotNull final Location location) {
+        return new ArrayList<>(children)
+                .get(NumberUtils.randInt(0, children.size() - 1))
+                .spawn(location);
+    }
+
+    /**
+     * Get the children.
+     *
+     * @return The children.
+     */
+    public Collection<TestableEntity> getChildren() {
+        return new ArrayList<>(children);
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/entities/impl/ModifiedTestableEntity.java

@@ -0,0 +1,69 @@
+package com.willfp.eco.core.entities.impl;
+
+import com.willfp.eco.core.entities.TestableEntity;
+import org.apache.commons.lang.Validate;
+import org.bukkit.Location;
+import org.bukkit.entity.Entity;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.function.Function;
+import java.util.function.Predicate;
+
+/**
+ * Existing testable entity with an extra filter.
+ *
+ * @see com.willfp.eco.core.entities.CustomEntity
+ */
+public class ModifiedTestableEntity implements TestableEntity {
+    /**
+     * The item.
+     */
+    private final TestableEntity handle;
+
+    /**
+     * The amount.
+     */
+    private final Predicate<Entity> test;
+
+    /**
+     * The provider to spawn the entity.
+     */
+    private final Function<Location, Entity> provider;
+
+    /**
+     * Create a new modified testable entity.
+     *
+     * @param entity   The base entity.
+     * @param test     The test.
+     * @param provider The provider to spawn the entity.
+     */
+    public ModifiedTestableEntity(@NotNull final TestableEntity entity,
+                                  @NotNull final Predicate<@NotNull Entity> test,
+                                  @NotNull final Function<Location, Entity> provider) {
+        this.handle = entity;
+        this.test = test;
+        this.provider = provider;
+    }
+
+    @Override
+    public boolean matches(@Nullable final Entity entity) {
+        return entity != null && handle.matches(entity) && test.test(entity);
+    }
+
+    @Override
+    public Entity spawn(@NotNull final Location location) {
+        Validate.notNull(location.getWorld());
+
+        return provider.apply(location);
+    }
+
+    /**
+     * Get the handle.
+     *
+     * @return The handle.
+     */
+    public TestableEntity getHandle() {
+        return this.handle;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/entities/impl/SimpleTestableEntity.java

@@ -0,0 +1,53 @@
+package com.willfp.eco.core.entities.impl;
+
+import com.willfp.eco.core.entities.TestableEntity;
+import org.apache.commons.lang.Validate;
+import org.bukkit.Location;
+import org.bukkit.entity.Entity;
+import org.bukkit.entity.EntityType;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Default vanilla entities.
+ */
+public class SimpleTestableEntity implements TestableEntity {
+    /**
+     * The entity type.
+     */
+    private final EntityType type;
+
+    /**
+     * Create a new simple testable entity.
+     *
+     * @param type The entity type.
+     */
+    public SimpleTestableEntity(@NotNull final EntityType type) {
+        this.type = type;
+
+        Validate.notNull(type.getEntityClass(), "Entity cannot be of unknown type!");
+    }
+
+    @Override
+    public boolean matches(@Nullable final Entity entity) {
+        return entity != null && entity.getType() == type;
+    }
+
+    @Override
+    public Entity spawn(@NotNull final Location location) {
+        Validate.notNull(location.getWorld());
+
+        assert type.getEntityClass() != null;
+
+        return location.getWorld().spawn(location, type.getEntityClass());
+    }
+
+    /**
+     * Get the type.
+     *
+     * @return The type.
+     */
+    public EntityType getType() {
+        return this.type;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/events/ArmorChangeEvent.java

@@ -0,0 +1,84 @@
+package com.willfp.eco.core.events;
+
+import org.bukkit.entity.Player;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.player.PlayerEvent;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.List;
+
+/**
+ * The armor change event <b>does</b> contain information about the event.
+ * <p>
+ * Unlike {@link ArmorEquipEvent}, it is called the next tick and contains previous and current armor contents.
+ */
+public class ArmorChangeEvent extends PlayerEvent {
+    /**
+     * Bukkit parity.
+     */
+    private static final HandlerList HANDLERS = new HandlerList();
+
+    /**
+     * The armor contents before. 0 is helmet, 3 is boots.
+     */
+    private final List<ItemStack> before;
+
+    /**
+     * The armor contents after. 0 is helmet, 3 is boots.
+     */
+    private final List<ItemStack> after;
+
+    /**
+     * Create a new ArmorChangeEvent.
+     *
+     * @param player The player.
+     * @param before The armor contents before.
+     * @param after  The armor contents after.
+     */
+    public ArmorChangeEvent(@NotNull final Player player,
+                            @NotNull final List<ItemStack> before,
+                            @NotNull final List<ItemStack> after) {
+        super(player);
+        this.before = before;
+        this.after = after;
+    }
+
+    /**
+     * Gets a list of handlers handling this event.
+     *
+     * @return A list of handlers handling this event.
+     */
+    @Override
+    @NotNull
+    public HandlerList getHandlers() {
+        return HANDLERS;
+    }
+
+    /**
+     * Bukkit parity.
+     *
+     * @return The handler list.
+     */
+    public static HandlerList getHandlerList() {
+        return HANDLERS;
+    }
+
+    /**
+     * Get the contents before the change.
+     *
+     * @return The contents.
+     */
+    public List<ItemStack> getBefore() {
+        return this.before;
+    }
+
+    /**
+     * Get the current contents.
+     *
+     * @return The contents.
+     */
+    public List<ItemStack> getAfter() {
+        return this.after;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/events/ArmorEquipEvent.java

@@ -0,0 +1,54 @@
+package com.willfp.eco.core.events;
+
+import org.bukkit.entity.Player;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.player.PlayerEvent;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * The armor equip event <b>does not contain information about the event.</b>
+ * <p>
+ * It is purely a trigger called whenever a player changes armor, you have to run
+ * your own checks.
+ * <p>
+ * The event is called before the player's inventory actually updates,
+ * so you can check a tick later to see the new contents.
+ *
+ * @see ArmorChangeEvent
+ */
+public class ArmorEquipEvent extends PlayerEvent {
+    /**
+     * Bukkit parity.
+     */
+    private static final HandlerList HANDLERS = new HandlerList();
+
+    /**
+     * Create a new ArmorEquipEvent.
+     *
+     * @param player The player.
+     */
+    public ArmorEquipEvent(@NotNull final Player player) {
+        super(player);
+    }
+
+    /**
+     * Gets a list of handlers handling this event.
+     *
+     * @return A list of handlers handling this event.
+     */
+
+    @Override
+    @NotNull
+    public HandlerList getHandlers() {
+        return HANDLERS;
+    }
+
+    /**
+     * Bukkit parity.
+     *
+     * @return The handler list.
+     */
+    public static HandlerList getHandlerList() {
+        return HANDLERS;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/events/DropQueuePushEvent.java

@@ -0,0 +1,143 @@
+package com.willfp.eco.core.events;
+
+import org.bukkit.Location;
+import org.bukkit.entity.Player;
+import org.bukkit.event.Cancellable;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.player.PlayerEvent;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.Collection;
+
+/**
+ * Called on DropQueue push.
+ */
+public class DropQueuePushEvent extends PlayerEvent implements Cancellable {
+    /**
+     * Cancel state.
+     */
+    private boolean cancelled;
+
+    /**
+     * If telekinetic.
+     */
+    private final boolean isTelekinetic;
+
+    /**
+     * The items.
+     */
+    private final Collection<? extends ItemStack> items;
+
+    /**
+     * The xp.
+     */
+    private final int xp;
+
+    /**
+     * The location.
+     */
+    private final Location location;
+
+    /**
+     * Bukkit parity.
+     */
+    private static final HandlerList HANDLERS = new HandlerList();
+
+    /**
+     * Create a new DropQueuePushEvent.
+     *
+     * @param player        The player.
+     * @param items         The items.
+     * @param location      The location.
+     * @param xp            The xp.
+     * @param isTelekinetic If the event is telekinetic.
+     */
+    public DropQueuePushEvent(@NotNull final Player player,
+                              @NotNull final Collection<? extends ItemStack> items,
+                              @NotNull final Location location,
+                              final int xp,
+                              final boolean isTelekinetic) {
+        super(player);
+        this.items = items;
+        this.location = location;
+        this.xp = xp;
+        this.isTelekinetic = isTelekinetic;
+    }
+
+    /**
+     * Gets a list of handlers handling this event.
+     *
+     * @return A list of handlers handling this event.
+     */
+    @Override
+    @NotNull
+    public HandlerList getHandlers() {
+        return HANDLERS;
+    }
+
+    /**
+     * Bukkit parity.
+     *
+     * @return The handler list.
+     */
+    public static HandlerList getHandlerList() {
+        return HANDLERS;
+    }
+
+    /**
+     * Get cancel state.
+     *
+     * @return The cancel state.
+     */
+    @Override
+    public boolean isCancelled() {
+        return this.cancelled;
+    }
+
+    /**
+     * Set cancel state.
+     *
+     * @param cancelled If cancelled.
+     */
+    @Override
+    public void setCancelled(final boolean cancelled) {
+        this.cancelled = cancelled;
+    }
+
+    /**
+     * Get the items to be dropped.
+     *
+     * @return The items.
+     */
+    public Collection<? extends ItemStack> getItems() {
+        return items;
+    }
+
+    /**
+     * Get the xp to be dropped.
+     *
+     * @return The xp.
+     */
+    public int getXp() {
+        return xp;
+    }
+
+    /**
+     * Get the location.
+     *
+     * @return The location.
+     */
+    public Location getLocation() {
+        return location;
+    }
+
+    /**
+     * Get force telekinesis state.
+     *
+     * @return The force telekinesis state.
+     */
+    public boolean isTelekinetic() {
+        return this.isTelekinetic;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/events/EntityDeathByEntityEvent.java

@@ -1,6 +1,5 @@
-package com.willfp.eco.util.events.entitydeathbyentity;
+package com.willfp.eco.core.events;
 
-import lombok.Getter;
 import org.bukkit.entity.Entity;
 import org.bukkit.entity.LivingEntity;
 import org.bukkit.event.Event;
@@ -12,7 +11,9 @@ import org.jetbrains.annotations.NotNull;
 import java.util.List;
 
 /**
- * Event triggered when entity is killed by entity.
+ * Event called when an entity is killed by another entity.
+ * <p>
+ * Not sure why spigot doesn't have this event normally.
  */
 public class EntityDeathByEntityEvent extends Event {
     /**
@@ -23,31 +24,26 @@ public class EntityDeathByEntityEvent extends Event {
     /**
      * The {@link LivingEntity} killed.
      */
-    @Getter
     private final LivingEntity victim;
 
     /**
      * The {@link Entity} that killed.
      */
-    @Getter
     private final Entity killer;
 
     /**
      * The associated {@link EntityDeathEvent}.
      */
-    @Getter
     private final EntityDeathEvent deathEvent;
 
     /**
      * The entity drops.
      */
-    @Getter
     private final List<ItemStack> drops;
 
     /**
      * The xp to drop.
      */
-    @Getter
     private final int xp;
 
     /**
@@ -89,4 +85,49 @@ public class EntityDeathByEntityEvent extends Event {
     public static HandlerList getHandlerList() {
         return HANDLERS;
     }
+
+    /**
+     * Get the entity killed.
+     *
+     * @return The victim.
+     */
+    public LivingEntity getVictim() {
+        return this.victim;
+    }
+
+    /**
+     * Get the killer.
+     *
+     * @return The killer.
+     */
+    public Entity getKiller() {
+        return this.killer;
+    }
+
+    /**
+     * Get the death event that caused this event.
+     *
+     * @return The death event.
+     */
+    public EntityDeathEvent getDeathEvent() {
+        return this.deathEvent;
+    }
+
+    /**
+     * Get the drops.
+     *
+     * @return The drops.
+     */
+    public List<ItemStack> getDrops() {
+        return this.drops;
+    }
+
+    /**
+     * Get the experience dropped.
+     *
+     * @return The experience.
+     */
+    public int getXp() {
+        return this.xp;
+    }
 }

eco-api/src/main/java/com/willfp/eco/core/events/EventManager.java

@@ -1,21 +1,25 @@
-package com.willfp.eco.util.bukkit.events;
+package com.willfp.eco.core.events;
 
 import org.bukkit.event.Listener;
+import org.jetbrains.annotations.NotNull;
 
+/**
+ * Manages listeners for a plugin.
+ */
 public interface EventManager {
     /**
      * Register a listener with bukkit.
      *
      * @param listener The listener to register.
      */
-    void registerListener(Listener listener);
+    void registerListener(@NotNull Listener listener);
 
     /**
      * Unregister a listener with bukkit.
      *
      * @param listener The listener to unregister.
      */
-    void unregisterListener(Listener listener);
+    void unregisterListener(@NotNull Listener listener);
 
     /**
      * Unregister all listeners associated with the plugin.

eco-api/src/main/java/com/willfp/eco/core/events/NaturalExpGainEvent.java

@@ -1,11 +1,14 @@
-package com.willfp.eco.util.events.naturalexpgainevent;
+package com.willfp.eco.core.events;
 
-import lombok.Getter;
 import org.bukkit.event.Event;
 import org.bukkit.event.HandlerList;
 import org.bukkit.event.player.PlayerExpChangeEvent;
 import org.jetbrains.annotations.NotNull;
 
+/**
+ * Event similar to {@link PlayerExpChangeEvent}, except it
+ * isn't called if the exp is from a bottle.
+ */
 public class NaturalExpGainEvent extends Event {
     /**
      * Internal bukkit.
@@ -16,7 +19,6 @@ public class NaturalExpGainEvent extends Event {
      * The associated {@link PlayerExpChangeEvent}.
      * Use this to modify event parameters.
      */
-    @Getter
     private final PlayerExpChangeEvent expChangeEvent;
 
     /**
@@ -46,4 +48,13 @@ public class NaturalExpGainEvent extends Event {
     public static HandlerList getHandlerList() {
         return HANDLERS;
     }
+
+    /**
+     * Get the event that caused this event.
+     *
+     * @return The exp change event.
+     */
+    public PlayerExpChangeEvent getExpChangeEvent() {
+        return this.expChangeEvent;
+    }
 }

eco-api/src/main/java/com/willfp/eco/core/events/PlayerJumpEvent.java

@@ -0,0 +1,84 @@
+package com.willfp.eco.core.events;
+
+import org.bukkit.Location;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.player.PlayerMoveEvent;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+/**
+ * Event called when a player jumps.
+ */
+public class PlayerJumpEvent extends PlayerMoveEvent {
+    /**
+     * Internal bukkit.
+     */
+    private static final HandlerList HANDLERS = new HandlerList();
+
+    /**
+     * The handled event.
+     */
+    private final PlayerMoveEvent handle;
+
+    /**
+     * Create a new PlayerJumpEvent.
+     *
+     * @param event The PlayerMoveEvent.
+     */
+    public PlayerJumpEvent(@NotNull final PlayerMoveEvent event) {
+        super(event.getPlayer(), event.getFrom(), event.getTo());
+
+        this.handle = event;
+    }
+
+    /**
+     * Internal bukkit.
+     *
+     * @return The handlers.
+     */
+    @Override
+    public @NotNull HandlerList getHandlers() {
+        return HANDLERS;
+    }
+
+    /**
+     * Internal bukkit.
+     *
+     * @return The handlers.
+     */
+    public static @NotNull HandlerList getHandlerList() {
+        return HANDLERS;
+    }
+
+    @Override
+    public boolean isCancelled() {
+        return handle.isCancelled();
+    }
+
+    @Override
+    public void setCancelled(final boolean cancel) {
+        handle.setCancelled(cancel);
+    }
+
+    @NotNull
+    @Override
+    public Location getFrom() {
+        return handle.getFrom();
+    }
+
+    @Override
+    public void setFrom(@NotNull final Location from) {
+        handle.setFrom(from);
+    }
+
+    @Nullable
+    @Override
+    public Location getTo() {
+        return handle.getTo();
+    }
+
+    @Override
+    public void setTo(@NotNull final Location to) {
+        handle.setTo(to);
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/extensions/Extension.java

@@ -0,0 +1,160 @@
+package com.willfp.eco.core.extensions;
+
+import com.willfp.eco.core.EcoPlugin;
+import com.willfp.eco.core.PluginLike;
+import com.willfp.eco.core.config.updating.ConfigHandler;
+import org.apache.commons.lang.Validate;
+import org.jetbrains.annotations.NotNull;
+
+import java.io.File;
+import java.util.logging.Logger;
+
+/**
+ * An extension is a separate jar file that hooks into the base plugin jar.
+ * <p>
+ * If you take PlaceholderAPI as an example, the PAPI expansions are identical to
+ * extensions.
+ * <p>
+ * Syntactically, extensions are very similar to plugins in their own right, except that
+ * they are loaded by another plugin.
+ *
+ * @see <a href="https://auxilor.polymart.org">Extension examples.</a>
+ */
+public abstract class Extension implements PluginLike {
+    /**
+     * The {@link EcoPlugin} that this extension is for.
+     */
+    private final EcoPlugin plugin;
+
+    /**
+     * Create a new extension for a plugin.
+     *
+     * @param plugin The plugin.
+     */
+    protected Extension(@NotNull final EcoPlugin plugin) {
+        this.plugin = plugin;
+    }
+
+    /**
+     * Metadata containing version and name.
+     */
+    private ExtensionMetadata metadata = null;
+
+    /**
+     * Method to validate metadata and enable extension.
+     */
+    public final void enable() {
+        Validate.notNull(metadata, "Metadata cannot be null!");
+        this.onEnable();
+    }
+
+    /**
+     * Method to disable extension.
+     */
+    public final void disable() {
+        this.onDisable();
+    }
+
+    /**
+     * Method to handle after load.
+     */
+    public final void handleAfterLoad() {
+        this.onAfterLoad();
+    }
+
+    /**
+     * Method to handle plugin reloads.
+     */
+    public final void handleReload() {
+        this.onReload();
+    }
+
+    /**
+     * Called on enabling Extension.
+     */
+    protected abstract void onEnable();
+
+    /**
+     * Called when Extension is disabled.
+     */
+    protected abstract void onDisable();
+
+    /**
+     * Called the once the base plugin is done loading.
+     */
+    protected void onAfterLoad() {
+        // Override if needed
+    }
+
+    /**
+     * Called on plugin reload.
+     */
+    protected void onReload() {
+        // Override if needed
+    }
+
+    /**
+     * Set the metadata of the extension.
+     * <p>
+     * Must be called before enabling.
+     *
+     * @param metadata The metadata to set.
+     */
+    public final void setMetadata(@NotNull final ExtensionMetadata metadata) {
+        this.metadata = metadata;
+    }
+
+    /**
+     * Get the name of the extension.
+     *
+     * @return The name of the metadata attached to the extension.
+     */
+    public final String getName() {
+        Validate.notNull(metadata, "Metadata cannot be null!");
+        return this.metadata.name();
+    }
+
+    /**
+     * Get the author of the extension.
+     *
+     * @return The author of the metadata attached to the extension.
+     */
+    public final String getAuthor() {
+        Validate.notNull(metadata, "Metadata cannot be null!");
+        return this.metadata.author();
+    }
+
+    /**
+     * Get the version of the extension.
+     *
+     * @return The version of the metadata attached to the extension.
+     */
+    public final String getVersion() {
+        Validate.notNull(metadata, "Metadata cannot be null!");
+        return this.metadata.version();
+    }
+
+    @Override
+    public File getDataFolder() {
+        return this.plugin.getDataFolder();
+    }
+
+    @Override
+    public ConfigHandler getConfigHandler() {
+        return this.plugin.getConfigHandler();
+    }
+
+    @Override
+    public Logger getLogger() {
+        return this.plugin.getLogger();
+    }
+
+    /**
+     * Get the plugin for the extension.
+     *
+     * @return The plugin.
+     */
+    protected EcoPlugin getPlugin() {
+        return this.plugin;
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/extensions/ExtensionLoader.java

@@ -1,15 +1,11 @@
-package com.willfp.eco.util.extensions.loader;
+package com.willfp.eco.core.extensions;
-
-import com.willfp.eco.util.extensions.Extension;
 
 import java.util.Set;
 
 /**
- * Interface for extension loader.
+ * Internal component to manage loading and unloading extensions.
- * Some external plugins may modify extension loading for internal server purposes.
  */
 public interface ExtensionLoader {
-
     /**
      * Load all extensions.
      */
@@ -20,11 +16,6 @@ public interface ExtensionLoader {
      */
     void unloadExtensions();
 
-    /**
-     * Reload all extensions.
-     */
-    void reloadExtensions();
-
     /**
      * Retrieve a set of all loaded extensions.
      *

eco-api/src/main/java/com/willfp/eco/core/extensions/ExtensionMetadata.java

@@ -0,0 +1,18 @@
+package com.willfp.eco.core.extensions;
+
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * The extension's metadata.
+ * <p>
+ * Stored as a record internally.
+ *
+ * @param version The extension version.
+ * @param name    The extension name.
+ * @param author  The extension's author.
+ */
+public record ExtensionMetadata(@NotNull String version,
+                                @NotNull String name,
+                                @NotNull String author) {
+
+}

eco-api/src/main/java/com/willfp/eco/core/extensions/MalformedExtensionException.java

@@ -1,18 +1,15 @@
-package com.willfp.eco.util.extensions;
+package com.willfp.eco.core.extensions;
 
 import org.jetbrains.annotations.NotNull;
 
 /**
- * Called when the extension is made incorrectly.
+ * Potential causes include:
+ * Missing or invalid extension.yml.
+ * Invalid filetype.
  */
 public class MalformedExtensionException extends RuntimeException {
-
     /**
      * Create a new MalformedExtensionException.
-     * <p>
-     * Potential causes include:
-     * Missing or invalid extension.yml.
-     * Invalid filetype.
      *
      * @param errorMessage The error message to show.
      */

eco-api/src/main/java/com/willfp/eco/core/factory/MetadataValueFactory.java

@@ -0,0 +1,17 @@
+package com.willfp.eco.core.factory;
+
+import org.bukkit.metadata.FixedMetadataValue;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Factory to create metadata values for a specific plugin.
+ */
+public interface MetadataValueFactory {
+    /**
+     * Create a metadata value for a given plugin and object.
+     *
+     * @param value The object to store in metadata.
+     * @return The metadata value.
+     */
+    FixedMetadataValue create(@NotNull Object value);
+}

eco-api/src/main/java/com/willfp/eco/core/factory/NamespacedKeyFactory.java

@@ -0,0 +1,17 @@
+package com.willfp.eco.core.factory;
+
+import org.bukkit.NamespacedKey;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Factory to create {@link NamespacedKey}s for a plugin.
+ */
+public interface NamespacedKeyFactory {
+    /**
+     * Create an {@link NamespacedKey} associated with an {@link com.willfp.eco.core.EcoPlugin}.
+     *
+     * @param key The key in the {@link NamespacedKey}.
+     * @return The created {@link NamespacedKey}.
+     */
+    NamespacedKey create(@NotNull String key);
+}

eco-api/src/main/java/com/willfp/eco/core/factory/RunnableFactory.java

@@ -0,0 +1,20 @@
+package com.willfp.eco.core.factory;
+
+import com.willfp.eco.core.scheduling.RunnableTask;
+import org.jetbrains.annotations.NotNull;
+
+import java.util.function.Consumer;
+
+/**
+ * Factory to create runnables. Much cleaner syntax than instantiating
+ * {@link org.bukkit.scheduler.BukkitRunnable}s.
+ */
+public interface RunnableFactory {
+    /**
+     * Create a {@link RunnableTask}.
+     *
+     * @param consumer Lambda of the code to run, where the parameter represents the instance of the runnable.
+     * @return The created {@link RunnableTask}.
+     */
+    RunnableTask create(@NotNull Consumer<RunnableTask> consumer);
+}

eco-api/src/main/java/com/willfp/eco/core/fast/FastItemStack.java

@@ -0,0 +1,135 @@
+package com.willfp.eco.core.fast;
+
+import com.willfp.eco.core.Eco;
+import org.bukkit.Material;
+import org.bukkit.enchantments.Enchantment;
+import org.bukkit.inventory.ItemFlag;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Set;
+
+/**
+ * FastItemStack contains methods to modify and read items faster than in default bukkit.
+ */
+public interface FastItemStack {
+    /**
+     * Get all enchantments on an item.
+     *
+     * @param checkStored If stored NBT should also be checked.
+     * @return A map of all enchantments.
+     * @deprecated Poorly named method. Use getEnchants instead.
+     */
+    @Deprecated(since = "6.24.0")
+    default Map<Enchantment, Integer> getEnchantmentsOnItem(boolean checkStored) {
+        return getEnchants(checkStored);
+    }
+
+    /**
+     * Get all enchantments on an item.
+     * Does not account for stored enchants.
+     *
+     * @return A map of all enchantments.
+     */
+    default Map<Enchantment, Integer> getEnchants() {
+        return getEnchants(false);
+    }
+
+    /**
+     * Get all enchantments on an item.
+     *
+     * @param checkStored If stored enchantments should be accounted for.
+     * @return A map of all enchantments.
+     */
+    Map<Enchantment, Integer> getEnchants(boolean checkStored);
+
+    /**
+     * Get the level of an enchantment on an item.
+     *
+     * @param enchantment The enchantment.
+     * @param checkStored If the stored NBT should also be checked.
+     * @return The enchantment level, or 0 if not found.
+     */
+    int getLevelOnItem(@NotNull Enchantment enchantment,
+                       boolean checkStored);
+
+    /**
+     * Set the item lore.
+     *
+     * @param lore The lore.
+     */
+    void setLore(@Nullable List<String> lore);
+
+    /**
+     * Get the item lore.
+     *
+     * @return The lore.
+     */
+    List<String> getLore();
+
+
+    /**
+     * Set the rework penalty.
+     *
+     * @param cost The rework penalty to set.
+     */
+    void setRepairCost(int cost);
+
+    /**
+     * Get the rework penalty.
+     * .
+     *
+     * @return The rework penalty found on the item.
+     */
+    int getRepairCost();
+
+    /**
+     * Add ItemFlags.
+     *
+     * @param hideFlags The flags.
+     */
+    void addItemFlags(@NotNull ItemFlag... hideFlags);
+
+    /**
+     * Remove ItemFlags.
+     *
+     * @param hideFlags The flags.
+     */
+    void removeItemFlags(@NotNull ItemFlag... hideFlags);
+
+    /**
+     * Get the ItemFlags.
+     *
+     * @return The flags.
+     */
+    Set<ItemFlag> getItemFlags();
+
+    /**
+     * Test the item for a flag.
+     *
+     * @param flag The flag.
+     * @return If the flag is present.
+     */
+    boolean hasItemFlag(@NotNull ItemFlag flag);
+
+    /**
+     * Get the Bukkit ItemStack again.
+     *
+     * @return The ItemStack.
+     */
+    ItemStack unwrap();
+
+    /**
+     * Wrap an ItemStack to create a FastItemStack.
+     *
+     * @param itemStack The ItemStack.
+     * @return The FastItemStack.
+     */
+    static FastItemStack wrap(@Nullable final ItemStack itemStack) {
+        return Eco.getHandler().createFastItemStack(Objects.requireNonNullElseGet(itemStack, () -> new ItemStack(Material.AIR)));
+    }
+}

eco-api/src/main/java/com/willfp/eco/core/gui/GUIFactory.java

@@ -0,0 +1,33 @@
+package com.willfp.eco.core.gui;
+
+import com.willfp.eco.core.Eco;
+import com.willfp.eco.core.gui.menu.MenuBuilder;
+import com.willfp.eco.core.gui.slot.SlotBuilder;
+import com.willfp.eco.core.gui.slot.functional.SlotProvider;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Internal component used by {@link com.willfp.eco.core.gui.menu.Menu#builder(int)}
+ * and {@link com.willfp.eco.core.gui.slot.Slot#builder(ItemStack)}.
+ */
+@ApiStatus.Internal
+@Eco.HandlerComponent
+public interface GUIFactory {
+    /**
+     * Create slot builder.
+     *
+     * @param provider The provider.
+     * @return The builder.
+     */
+    SlotBuilder createSlotBuilder(@NotNull SlotProvider provider);
+
+    /**
+     * Create menu builder.
+     *
+     * @param rows The amount of rows.
+     * @return The builder.
+     */
+    MenuBuilder createMenuBuilder(int rows);
+}

eco-api/src/main/java/com/willfp/eco/core/gui/menu/CloseHandler.java

@@ -0,0 +1,19 @@
+package com.willfp.eco.core.gui.menu;
+
+import org.bukkit.event.inventory.InventoryCloseEvent;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * Interface to run on menu close.
+ */
+@FunctionalInterface
+public interface CloseHandler {
+    /**
+     * Performs this operation on the given arguments.
+     *
+     * @param event The close event.
+     * @param menu  The menu.
+     */
+    void handle(@NotNull InventoryCloseEvent event,
+                @NotNull Menu menu);
+}