diff --git a/deob/src/main/java/dev/openrs2/deob/transform/OriginalNameTransformer.java b/deob/src/main/java/dev/openrs2/deob/transform/OriginalNameTransformer.java
deleted file mode 100644
index 53dac0b0cf..0000000000
--- a/deob/src/main/java/dev/openrs2/deob/transform/OriginalNameTransformer.java
+++ /dev/null
@@ -1,88 +0,0 @@
-package dev.openrs2.deob.transform;
-
-import java.util.ArrayList;
-import java.util.List;
-
-import com.google.common.collect.ImmutableList;
-import dev.openrs2.asm.classpath.ClassPath;
-import dev.openrs2.asm.classpath.Library;
-import dev.openrs2.asm.transform.Transformer;
-import dev.openrs2.deob.annotation.OriginalArg;
-import dev.openrs2.deob.annotation.OriginalClass;
-import dev.openrs2.deob.annotation.OriginalMember;
-import org.objectweb.asm.Type;
-import org.objectweb.asm.tree.AnnotationNode;
-import org.objectweb.asm.tree.ClassNode;
-import org.objectweb.asm.tree.FieldNode;
-import org.objectweb.asm.tree.MethodNode;
-
-public final class OriginalNameTransformer extends Transformer {
-	private static AnnotationNode createOriginalClassAnnotation(String name) {
-		var annotation = new AnnotationNode(Type.getDescriptor(OriginalClass.class));
-		annotation.values = ImmutableList.of("value", name);
-		return annotation;
-	}
-
-	private static AnnotationNode createOriginalMemberAnnotation(String owner, String name, String desc) {
-		var annotation = new AnnotationNode(Type.getDescriptor(OriginalMember.class));
-		annotation.values = ImmutableList.of(
-			"owner", owner,
-			"name", name,
-			"descriptor", desc
-		);
-		return annotation;
-	}
-
-	private static AnnotationNode createOriginalArgAnnotation(int index) {
-		var annotation = new AnnotationNode(Type.getDescriptor(OriginalArg.class));
-		annotation.values = ImmutableList.of("value", index);
-		return annotation;
-	}
-
-	@Override
-	public boolean transformClass(ClassPath classPath, Library library, ClassNode clazz) {
-		if (clazz.invisibleAnnotations == null) {
-			clazz.invisibleAnnotations = new ArrayList<>();
-		}
-		clazz.invisibleAnnotations.add(createOriginalClassAnnotation(clazz.name));
-
-		return false;
-	}
-
-	@Override
-	public boolean transformField(ClassPath classPath, Library library, ClassNode clazz, FieldNode field) {
-		if (field.invisibleAnnotations == null) {
-			field.invisibleAnnotations = new ArrayList<>();
-		}
-		field.invisibleAnnotations.add(createOriginalMemberAnnotation(clazz.name, field.name, field.desc));
-
-		return false;
-	}
-
-	@SuppressWarnings("unchecked")
-	@Override
-	public boolean preTransformMethod(ClassPath classPath, Library library, ClassNode clazz, MethodNode method) {
-		if (method.name.equals("<init>") || method.name.equals("<clinit>")) {
-			return false;
-		}
-
-		if (method.invisibleAnnotations == null) {
-			method.invisibleAnnotations = new ArrayList<>();
-		}
-		method.invisibleAnnotations.add(createOriginalMemberAnnotation(clazz.name, method.name, method.desc));
-
-		int args = Type.getArgumentTypes(method.desc).length;
-		if (method.invisibleParameterAnnotations == null) {
-			method.invisibleParameterAnnotations = (List<AnnotationNode>[]) new List<?>[args];
-		}
-		for (var i = 0; i < method.invisibleParameterAnnotations.length; i++) {
-			var annotations = method.invisibleParameterAnnotations[i];
-			if (annotations == null) {
-				annotations = method.invisibleParameterAnnotations[i] = new ArrayList<>();
-			}
-			annotations.add(createOriginalArgAnnotation(i));
-		}
-
-		return false;
-	}
-}
diff --git a/deob/src/main/java/dev/openrs2/deob/transform/OriginalNameTransformer.kt b/deob/src/main/java/dev/openrs2/deob/transform/OriginalNameTransformer.kt
new file mode 100644
index 0000000000..d6c9d0cf0e
--- /dev/null
+++ b/deob/src/main/java/dev/openrs2/deob/transform/OriginalNameTransformer.kt
@@ -0,0 +1,91 @@
+package dev.openrs2.deob.transform
+
+import dev.openrs2.asm.classpath.ClassPath
+import dev.openrs2.asm.classpath.Library
+import dev.openrs2.asm.transform.Transformer
+import dev.openrs2.deob.annotation.OriginalArg
+import dev.openrs2.deob.annotation.OriginalClass
+import dev.openrs2.deob.annotation.OriginalMember
+import org.objectweb.asm.Type
+import org.objectweb.asm.tree.AnnotationNode
+import org.objectweb.asm.tree.ClassNode
+import org.objectweb.asm.tree.FieldNode
+import org.objectweb.asm.tree.MethodNode
+
+class OriginalNameTransformer : Transformer() {
+    public override fun transformClass(classPath: ClassPath, library: Library, clazz: ClassNode): Boolean {
+        if (clazz.invisibleAnnotations == null) {
+            clazz.invisibleAnnotations = mutableListOf()
+        }
+        clazz.invisibleAnnotations.add(createOriginalClassAnnotation(clazz.name))
+        return false
+    }
+
+    public override fun transformField(
+        classPath: ClassPath,
+        library: Library,
+        clazz: ClassNode,
+        field: FieldNode
+    ): Boolean {
+        if (field.invisibleAnnotations == null) {
+            field.invisibleAnnotations = mutableListOf()
+        }
+        field.invisibleAnnotations.add(createOriginalMemberAnnotation(clazz.name, field.name, field.desc))
+        return false
+    }
+
+    public override fun preTransformMethod(
+        classPath: ClassPath,
+        library: Library,
+        clazz: ClassNode,
+        method: MethodNode
+    ): Boolean {
+        if (method.name == "<init>" || method.name == "<clinit>") {
+            return false
+        }
+
+        if (method.invisibleAnnotations == null) {
+            method.invisibleAnnotations = mutableListOf()
+        }
+        method.invisibleAnnotations.add(createOriginalMemberAnnotation(clazz.name, method.name, method.desc))
+
+        val args = Type.getArgumentTypes(method.desc).size
+        if (method.invisibleParameterAnnotations == null) {
+            method.invisibleParameterAnnotations = arrayOfNulls(args)
+        }
+        for (i in method.invisibleParameterAnnotations.indices) {
+            var annotations = method.invisibleParameterAnnotations[i]
+            if (annotations == null) {
+                annotations = mutableListOf()
+                method.invisibleParameterAnnotations[i] = annotations
+            }
+            annotations.add(createOriginalArgAnnotation(i))
+        }
+
+        return false
+    }
+
+    companion object {
+        private fun createOriginalClassAnnotation(name: String): AnnotationNode {
+            val annotation = AnnotationNode(Type.getDescriptor(OriginalClass::class.java))
+            annotation.values = listOf("value", name)
+            return annotation
+        }
+
+        private fun createOriginalMemberAnnotation(owner: String, name: String, desc: String): AnnotationNode {
+            val annotation = AnnotationNode(Type.getDescriptor(OriginalMember::class.java))
+            annotation.values = listOf(
+                "owner", owner,
+                "name", name,
+                "descriptor", desc
+            )
+            return annotation
+        }
+
+        private fun createOriginalArgAnnotation(index: Int): AnnotationNode {
+            val annotation = AnnotationNode(Type.getDescriptor(OriginalArg::class.java))
+            annotation.values = listOf("value", index)
+            return annotation
+        }
+    }
+}