src/macosx/classes/sun/lwawt/macosx/CPlatformEmbeddedFrame.java

@@ -64,10 +64,16 @@
     public long getLayerPtr() {
         return windowLayer.getPointer();
     }
 
     @Override
+    public long getViewPtr() {
+        //Embedded frame is not view-backed
+        return 0;
+    }
+
+    @Override
     public void dispose() {
         windowLayer.dispose();
     }
 
     @Override