Refactor Animator class to use primitive boolean and add destroy method for resource management

Author: ninjz

android/gltfio-android/src/main/java/com/google/android/filament/gltfio/Animator.java

@@ -37,29 +37,27 @@
  */
 public class Animator {
     private long mNativeObject;
-    private Boolean mIsOwner = false;
+    private boolean mIsOwner = false;
 
     Animator(long nativeObject) {
         mNativeObject = nativeObject;
     }
 
+    /**
+     * Creates an Animator that can manipulate animations in the provided FilamentAsset.
+     * <p>
+     * <strong>Important:</strong> This Animator manages native resources that must be 
+     * explicitly freed by calling {@link #destroy()} when no longer needed. Failing to 
+     * call {@link #destroy()} will result in native memory leaks.
+     * </p>
+     *
+     * @param asset The FilamentAsset containing the animations
+     * @param instance The FilamentInstance to animate
+     */
     public Animator(FilamentAsset asset, FilamentInstance instance) {
         mNativeObject = nCreateAnimatorFromAssetAndInstance(asset.getNativeObject(), instance.getNativeObject());
         mIsOwner = true;
     }
-    
-    @Override
-    public void finalize() {
-        try {
-            super.finalize();
-        } catch (Throwable t) { // Ignore
-        } finally {
-            if (mIsOwner) {
-                nDestroyAnimator(mNativeObject);
-                mNativeObject = 0;
-            }
-        }
-    }
 
     /**
      * Applies rotation, translation, and scale to entities that have been targeted by the given
@@ -145,6 +143,19 @@ public String getAnimationName(@IntRange(from = 0) int animationIndex) {
         return nGetAnimationName(getNativeObject(), animationIndex);
     }
 
+    /**
+     * Explicitly destroys this Animator and frees all its associated native resources.
+     * The object will be unusable after this call.
+     */
+    public void destroy() {
+        if (mNativeObject != 0) {
+            if (mIsOwner) {
+                nDestroyAnimator(mNativeObject);
+            }
+            mNativeObject = 0;
+        }
+    }
+
     long getNativeObject() {
         if (mNativeObject == 0) {
             throw new IllegalStateException("Using Animator on destroyed asset");