diff --git a/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/behavior/CosmeticMovementBehavior.java b/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/behavior/CosmeticMovementBehavior.java
index ef4e7c92..4def909b 100644
--- a/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/behavior/CosmeticMovementBehavior.java
+++ b/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/behavior/CosmeticMovementBehavior.java
@@ -2,14 +2,15 @@ package com.hibiscusmc.hmccosmetics.cosmetic.behavior;
 
 import com.hibiscusmc.hmccosmetics.user.CosmeticUser;
 import org.bukkit.Location;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * Updates cosmetics whenever a player moves.
  */
 public interface CosmeticMovementBehavior {
     void dispatchMove(
-        final CosmeticUser user,
-        final Location from,
-        final Location to
+        @NotNull final CosmeticUser user,
+        @NotNull final Location from,
+        @NotNull final Location to
     );
 }
diff --git a/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/behavior/CosmeticUpdateBehavior.java b/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/behavior/CosmeticUpdateBehavior.java
index c7944485..4eaeb3f0 100644
--- a/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/behavior/CosmeticUpdateBehavior.java
+++ b/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/behavior/CosmeticUpdateBehavior.java
@@ -1,10 +1,13 @@
 package com.hibiscusmc.hmccosmetics.cosmetic.behavior;
 
 import com.hibiscusmc.hmccosmetics.user.CosmeticUser;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * Generic updates that happen every tick or when manually requested to be dispatched.
  */
 public interface CosmeticUpdateBehavior {
-    void dispatchUpdate(final CosmeticUser user);
+    void dispatchUpdate(
+            @NotNull final CosmeticUser user
+    );
 }
\ No newline at end of file
diff --git a/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/types/CosmeticArmorType.java b/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/types/CosmeticArmorType.java
index 890acf4f..ab20cc01 100644
--- a/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/types/CosmeticArmorType.java
+++ b/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/types/CosmeticArmorType.java
@@ -31,7 +31,7 @@ public class CosmeticArmorType extends Cosmetic implements CosmeticUpdateBehavio
     }
 
     @Override
-    public void dispatchUpdate(CosmeticUser user) {
+    public void dispatchUpdate(@NotNull CosmeticUser user) {
         if (user.isInWardrobe()) return;
         Entity entity = Bukkit.getEntity(user.getUniqueId());
         if (entity == null) return;
diff --git a/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/types/CosmeticBackpackType.java b/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/types/CosmeticBackpackType.java
index dfef6bc8..1302117c 100644
--- a/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/types/CosmeticBackpackType.java
+++ b/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/types/CosmeticBackpackType.java
@@ -39,7 +39,7 @@ public class CosmeticBackpackType extends Cosmetic implements CosmeticUpdateBeha
     }
 
     @Override
-    public void dispatchUpdate(CosmeticUser user) {
+    public void dispatchUpdate(@NotNull CosmeticUser user) {
         Entity entity = user.getEntity();
         if(entity == null) {
             return;
@@ -95,7 +95,7 @@ public class CosmeticBackpackType extends Cosmetic implements CosmeticUpdateBeha
     }
 
     @Override
-    public void dispatchMove(CosmeticUser user, Location from, Location to) {
+    public void dispatchMove(@NotNull CosmeticUser user, @NotNull Location from, @NotNull Location to) {
         @SuppressWarnings("DuplicatedCode") // thanks.
         Entity entity = user.getEntity();
         if(entity == null) {
diff --git a/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/types/CosmeticBalloonType.java b/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/types/CosmeticBalloonType.java
index 20a65d2d..c446e5b2 100644
--- a/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/types/CosmeticBalloonType.java
+++ b/common/src/main/java/com/hibiscusmc/hmccosmetics/cosmetic/types/CosmeticBalloonType.java
@@ -16,6 +16,7 @@ import org.bukkit.Location;
 import org.bukkit.entity.Entity;
 import org.bukkit.entity.Player;
 import org.bukkit.util.Vector;
+import org.jetbrains.annotations.NotNull;
 
 import java.util.List;
 
@@ -55,7 +56,7 @@ public class CosmeticBalloonType extends Cosmetic implements CosmeticUpdateBehav
     }
 
     @Override
-    public void dispatchUpdate(CosmeticUser user) {
+    public void dispatchUpdate(@NotNull CosmeticUser user) {
         Entity entity = Bukkit.getEntity(user.getUniqueId());
         UserBalloonManager userBalloonManager = user.getBalloonManager();
 
@@ -79,7 +80,7 @@ public class CosmeticBalloonType extends Cosmetic implements CosmeticUpdateBehav
     }
 
     @Override
-    public void dispatchMove(CosmeticUser user, Location from, Location to) {
+    public void dispatchMove(@NotNull CosmeticUser user, @NotNull Location from, @NotNull Location to) {
         Entity entity = Bukkit.getEntity(user.getUniqueId());
         UserBalloonManager userBalloonManager = user.getBalloonManager();