diff --git a/src/main/java/net/minecraft/server/IntHashMap.java b/src/main/java/net/minecraft/server/IntHashMap.java
new file mode 100644
index 000000000..596f3c061
--- /dev/null
+++ b/src/main/java/net/minecraft/server/IntHashMap.java
@@ -0,0 +1,243 @@
+package net.minecraft.server;
+
+import javax.annotation.Nullable;
+
+import com.koloboke.collect.map.hash.HashIntObjMap;
+import com.koloboke.collect.map.hash.HashIntObjMaps;
+
+public class IntHashMap<V> {
+
+    private final HashIntObjMap<V> map = HashIntObjMaps.newMutableMap(); // Akarin
+    @Deprecated private transient IntHashMap.IntHashMapEntry<V>[] a = (IntHashMap.IntHashMapEntry[]) (new IntHashMap.IntHashMapEntry[16]); // Akarin
+    @Deprecated private transient int b; // Akarin
+    @Deprecated private int c = 12; // Akarin
+    private final float d = 0.75F;
+
+    public IntHashMap() {}
+
+    @Deprecated // Akarin
+    private static int g(int i) {
+        i ^= i >>> 20 ^ i >>> 12;
+        return i ^ i >>> 7 ^ i >>> 4;
+    }
+
+    @Deprecated // Akarin
+    private static int a(int i, int j) {
+        return i & j - 1;
+    }
+
+    @Nullable
+    public V get(int i) {
+        // Akarin start
+        /*
+        int j = g(i);
+
+        for (IntHashMap.IntHashMapEntry inthashmap_inthashmapentry = this.a[a(j, this.a.length)]; inthashmap_inthashmapentry != null; inthashmap_inthashmapentry = inthashmap_inthashmapentry.c) {
+            if (inthashmap_inthashmapentry.a == i) {
+                return (V) inthashmap_inthashmapentry.b;
+            }
+        }
+
+        return null;
+        */
+        return map.get(i);
+        // Akarin end
+    }
+
+    public boolean b(int i) {
+        return map.containsKey(i); // Akarin
+    }
+
+    @Nullable
+    @Deprecated // Akarin
+    final IntHashMap.IntHashMapEntry<V> c(int i) {
+        int j = g(i);
+
+        for (IntHashMap.IntHashMapEntry inthashmap_inthashmapentry = this.a[a(j, this.a.length)]; inthashmap_inthashmapentry != null; inthashmap_inthashmapentry = inthashmap_inthashmapentry.c) {
+            if (inthashmap_inthashmapentry.a == i) {
+                return inthashmap_inthashmapentry;
+            }
+        }
+
+        return null;
+    }
+
+    public void a(int i, V v0) {
+        // Akarin start
+        /*
+        int j = g(i);
+        int k = a(j, this.a.length);
+
+        for (IntHashMap.IntHashMapEntry inthashmap_inthashmapentry = this.a[k]; inthashmap_inthashmapentry != null; inthashmap_inthashmapentry = inthashmap_inthashmapentry.c) {
+            if (inthashmap_inthashmapentry.a == i) {
+                inthashmap_inthashmapentry.b = v0;
+                return;
+            }
+        }
+
+        this.a(j, i, v0, k);
+        */
+        map.put(i, v0);
+     // Akarin end
+    }
+
+    @Deprecated // Akarin
+    private void h(int i) {
+        IntHashMap.IntHashMapEntry<V>[] ainthashmap_inthashmapentry = this.a;
+        int j = ainthashmap_inthashmapentry.length;
+
+        if (j == 1073741824) {
+            this.c = Integer.MAX_VALUE;
+        } else {
+            IntHashMap.IntHashMapEntry<V>[] ainthashmap_inthashmapentry1 = (IntHashMap.IntHashMapEntry[]) (new IntHashMap.IntHashMapEntry[i]);
+
+            this.a(ainthashmap_inthashmapentry1);
+            this.a = ainthashmap_inthashmapentry1;
+            this.c = (int) ((float) i * this.d);
+        }
+    }
+
+    @Deprecated // Akarin
+    private void a(IntHashMap.IntHashMapEntry<V>[] ainthashmap_inthashmapentry) {
+        IntHashMap.IntHashMapEntry<V>[] ainthashmap_inthashmapentry1 = this.a;
+        int i = ainthashmap_inthashmapentry.length;
+
+        for (int j = 0; j < ainthashmap_inthashmapentry1.length; ++j) {
+            IntHashMap.IntHashMapEntry<V> inthashmap_inthashmapentry = ainthashmap_inthashmapentry1[j];
+
+            if (inthashmap_inthashmapentry != null) {
+                ainthashmap_inthashmapentry1[j] = null;
+
+                IntHashMap.IntHashMapEntry inthashmap_inthashmapentry1;
+
+                do {
+                    inthashmap_inthashmapentry1 = inthashmap_inthashmapentry.c;
+                    int k = a(inthashmap_inthashmapentry.d, i);
+
+                    inthashmap_inthashmapentry.c = ainthashmap_inthashmapentry[k];
+                    ainthashmap_inthashmapentry[k] = inthashmap_inthashmapentry;
+                    inthashmap_inthashmapentry = inthashmap_inthashmapentry1;
+                } while (inthashmap_inthashmapentry1 != null);
+            }
+        }
+
+    }
+
+    @Nullable
+    public V d(int i) {
+        // Akarin start
+        /*
+        IntHashMap.IntHashMapEntry<V> inthashmap_inthashmapentry = this.e(i);
+
+        return inthashmap_inthashmapentry == null ? null : inthashmap_inthashmapentry.b;
+        */
+        return map.get(i);
+        // Akarin end
+    }
+
+    @Nullable
+    @Deprecated // Akarin
+    final IntHashMap.IntHashMapEntry<V> e(int i) {
+        int j = g(i);
+        int k = a(j, this.a.length);
+        IntHashMap.IntHashMapEntry<V> inthashmap_inthashmapentry = this.a[k];
+
+        IntHashMap.IntHashMapEntry inthashmap_inthashmapentry1;
+        IntHashMap.IntHashMapEntry inthashmap_inthashmapentry2;
+
+        for (inthashmap_inthashmapentry2 = inthashmap_inthashmapentry; inthashmap_inthashmapentry2 != null; inthashmap_inthashmapentry2 = inthashmap_inthashmapentry1) {
+            inthashmap_inthashmapentry1 = inthashmap_inthashmapentry2.c;
+            if (inthashmap_inthashmapentry2.a == i) {
+                --this.b;
+                if (inthashmap_inthashmapentry == inthashmap_inthashmapentry2) {
+                    this.a[k] = inthashmap_inthashmapentry1;
+                } else {
+                    inthashmap_inthashmapentry.c = inthashmap_inthashmapentry1;
+                }
+
+                return inthashmap_inthashmapentry2;
+            }
+
+            inthashmap_inthashmapentry = inthashmap_inthashmapentry2;
+        }
+
+        return inthashmap_inthashmapentry2;
+    }
+
+    public void c() {
+        // Akarin start
+        /*
+        IntHashMap.IntHashMapEntry<V>[] ainthashmap_inthashmapentry = this.a;
+
+        for (int i = 0; i < ainthashmap_inthashmapentry.length; ++i) {
+            ainthashmap_inthashmapentry[i] = null;
+        }
+
+        this.b = 0;
+        */
+        map.clear();
+        // Akarin end
+    }
+
+    @Deprecated // Akarin
+    private void a(int i, int j, V v0, int k) {
+        IntHashMap.IntHashMapEntry<V> inthashmap_inthashmapentry = this.a[k];
+
+        this.a[k] = new IntHashMap.IntHashMapEntry<>(i, j, v0, inthashmap_inthashmapentry);
+        if (this.b++ >= this.c) {
+            this.h(2 * this.a.length);
+        }
+
+    }
+
+    @Deprecated // Akarin
+    static class IntHashMapEntry<V> {
+
+        private final int a;
+        private V b;
+        private IntHashMap.IntHashMapEntry<V> c;
+        private final int d;
+
+        IntHashMapEntry(int i, int j, V v0, IntHashMap.IntHashMapEntry<V> inthashmap_inthashmapentry) {
+            this.b = v0;
+            this.c = inthashmap_inthashmapentry;
+            this.a = j;
+            this.d = i;
+        }
+
+        public final int a() {
+            return this.a;
+        }
+
+        public final V b() {
+            return this.b;
+        }
+
+        public final boolean equals(Object object) {
+            if (!(object instanceof IntHashMap.IntHashMapEntry)) {
+                return false;
+            } else {
+                IntHashMap.IntHashMapEntry<V> inthashmap_inthashmapentry = (IntHashMap.IntHashMapEntry) object;
+
+                if (this.a == inthashmap_inthashmapentry.a) {
+                    Object object1 = this.b();
+                    Object object2 = inthashmap_inthashmapentry.b();
+
+                    if (object1 == object2 || object1 != null && object1.equals(object2)) {
+                        return true;
+                    }
+                }
+
+                return false;
+            }
+        }
+
+        public final int hashCode() {
+            return IntHashMap.g(this.a);
+        }
+
+        public final String toString() {
+            return this.a() + "=" + this.b();
+        }
+    }
+}
diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
index 17e53ae13..46662ab08 100644
--- a/src/main/java/net/minecraft/server/World.java
+++ b/src/main/java/net/minecraft/server/World.java
@@ -28,6 +28,9 @@ import org.apache.logging.log4j.Logger;
 
 // CraftBukkit start
 import com.google.common.collect.Maps;
+import com.koloboke.collect.map.hash.HashObjObjMaps;
+import com.koloboke.collect.set.hash.HashObjSets;
+
 import java.util.ArrayList;
 import java.util.HashMap; // Paper
 import java.util.Map;
@@ -77,13 +80,13 @@ public abstract class World implements IEntityAccess, GeneratorAccess, IIBlockAc
     };
     */ // Paper end
     // Spigot end
-    protected final Set<Entity> g = com.google.common.collect.Sets.newHashSet(); public Set<Entity> getEntityUnloadQueue() { return g; };// Paper - OBFHELPER
+    protected final Set<Entity> g = HashObjSets.newMutableSet(); public Set<Entity> getEntityUnloadQueue() { return g; };// Paper - OBFHELPER // Akarin
     //public final List<TileEntity> tileEntityList = Lists.newArrayList(); // Paper - remove unused list
     public final List<TileEntity> tileEntityListTick = Lists.newArrayList();
     private final List<TileEntity> c = Lists.newArrayList();
-    private final Set<TileEntity> tileEntityListUnload = com.google.common.collect.Sets.newHashSet(); // Paper
+    private final Set<TileEntity> tileEntityListUnload = HashObjSets.newMutableSet(); // Paper // Akarin
     public final List<EntityHuman> players = Lists.newArrayList();
-    public final Map<String, EntityHuman> playersByName = Maps.newHashMap(); // Paper - World EntityHuman Lookup Optimizations
+    public final Map<String, EntityHuman> playersByName = HashObjObjMaps.newMutableMap(); // Paper - World EntityHuman Lookup Optimizations // Akarin
     public final List<Entity> k = Lists.newArrayList();
     protected final IntHashMap<Entity> entitiesById = new IntHashMap<>();
     private final long F = 16777215L;