diff --git a/src/main/java/net/minestom/server/extras/selfmodification/HierarchyClassLoader.java b/src/main/java/net/minestom/server/extras/selfmodification/HierarchyClassLoader.java
index 1c5ad5c34..be464fb26 100644
--- a/src/main/java/net/minestom/server/extras/selfmodification/HierarchyClassLoader.java
+++ b/src/main/java/net/minestom/server/extras/selfmodification/HierarchyClassLoader.java
@@ -22,20 +22,25 @@ public abstract class HierarchyClassLoader extends URLClassLoader {
         children.add(loader);
     }
 
-    public InputStream getResourceAsStreamWithChildren(String name) {
+    public InputStream getResourceAsStreamWithChildren(@NotNull String name) {
         InputStream in = getResourceAsStream(name);
-        if(in != null) return in;
+        if (in != null) return in;
 
-        for(MinestomExtensionClassLoader child : children) {
+        for (MinestomExtensionClassLoader child : children) {
             InputStream childInput = child.getResourceAsStreamWithChildren(name);
-            if(childInput != null)
+            if (childInput != null)
                 return childInput;
         }
+
         return null;
     }
 
     public void removeChildInHierarchy(MinestomExtensionClassLoader child) {
         children.remove(child);
-        children.forEach(c -> c.removeChildInHierarchy(child));
+
+        // Also remove all children from these extension's children.
+        for (MinestomExtensionClassLoader subChild : children) {
+            subChild.removeChildInHierarchy(child);
+        }
     }
 }
diff --git a/src/main/java/net/minestom/server/extras/selfmodification/MinestomExtensionClassLoader.java b/src/main/java/net/minestom/server/extras/selfmodification/MinestomExtensionClassLoader.java
index 24557d18b..5dbeb84d7 100644
--- a/src/main/java/net/minestom/server/extras/selfmodification/MinestomExtensionClassLoader.java
+++ b/src/main/java/net/minestom/server/extras/selfmodification/MinestomExtensionClassLoader.java
@@ -105,8 +105,14 @@ public class MinestomExtensionClassLoader extends HierarchyClassLoader {
      * @see MinestomRootClassLoader#loadBytes(String, boolean) for more information
      */
     protected boolean isMainExtensionClass(String name) {
-        if(mainClassName.equals(name))
+
+        if (mainClassName.equals(name))
             return true;
-        return children.stream().anyMatch(c -> c.isMainExtensionClass(name));
+
+        for (MinestomExtensionClassLoader child : children) {
+            if (child.isMainExtensionClass(name)) return true;
+        }
+
+        return false;
     }
 }
diff --git a/src/main/java/net/minestom/server/extras/selfmodification/MinestomRootClassLoader.java b/src/main/java/net/minestom/server/extras/selfmodification/MinestomRootClassLoader.java
index b1572aae3..0c0517e07 100644
--- a/src/main/java/net/minestom/server/extras/selfmodification/MinestomRootClassLoader.java
+++ b/src/main/java/net/minestom/server/extras/selfmodification/MinestomRootClassLoader.java
@@ -10,7 +10,6 @@ import org.objectweb.asm.tree.ClassNode;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.lang.reflect.InvocationTargetException;
@@ -220,9 +219,8 @@ public class MinestomRootClassLoader extends HierarchyClassLoader {
         return originalBytes;
     }
 
-    public byte[] loadBytesWithChildren(String name, boolean transform) throws IOException, ClassNotFoundException {
-        if (name == null)
-            throw new ClassNotFoundException();
+    public byte[] loadBytesWithChildren(@NotNull String name, boolean transform) throws IOException, ClassNotFoundException {
+
         String path = name.replace(".", "/") + ".class";
         InputStream input = getResourceAsStreamWithChildren(path);
         if (input == null) {
@@ -298,11 +296,7 @@ public class MinestomRootClassLoader extends HierarchyClassLoader {
             }
             return true;
         } catch (ClassNotFoundException | InvocationTargetException | InstantiationException | IllegalAccessException | NoSuchMethodException e) {
-            if(MinecraftServer.getExceptionManager() != null) {
-                MinecraftServer.getExceptionManager().handleException(e);
-            } else {
-                e.printStackTrace();
-            }
+            MinecraftServer.getExceptionManager().handleException(e);
         }
         return false;
     }
@@ -336,7 +330,7 @@ public class MinestomRootClassLoader extends HierarchyClassLoader {
     @Nullable
     public static String findExtensionObjectOwner(@NotNull Object obj) {
         ClassLoader cl = obj.getClass().getClassLoader();
-        if(cl instanceof MinestomExtensionClassLoader) {
+        if (cl instanceof MinestomExtensionClassLoader) {
             return ((MinestomExtensionClassLoader) cl).getExtensionName();
         }
         return null;
diff --git a/src/main/java/net/minestom/server/extras/selfmodification/mixins/MixinServiceMinestom.java b/src/main/java/net/minestom/server/extras/selfmodification/mixins/MixinServiceMinestom.java
index 5af794698..93b6e8ce2 100644
--- a/src/main/java/net/minestom/server/extras/selfmodification/mixins/MixinServiceMinestom.java
+++ b/src/main/java/net/minestom/server/extras/selfmodification/mixins/MixinServiceMinestom.java
@@ -1,6 +1,7 @@
 package net.minestom.server.extras.selfmodification.mixins;
 
 import net.minestom.server.extras.selfmodification.MinestomRootClassLoader;
+import org.jetbrains.annotations.NotNull;
 import org.spongepowered.asm.launch.platform.container.ContainerHandleVirtual;
 import org.spongepowered.asm.launch.platform.container.IContainerHandle;
 import org.spongepowered.asm.mixin.MixinEnvironment;
@@ -64,7 +65,7 @@ public class MixinServiceMinestom extends MixinServiceAbstract {
     }
 
     @Override
-    public InputStream getResourceAsStream(String name) {
+    public InputStream getResourceAsStream(@NotNull String name) {
         return classLoader.getResourceAsStreamWithChildren(name);
     }