public void deleteAllObjects(Object rendererObject){
        deleteUnused(rendererObject);
        ArrayList<NativeObjectRef> refMapCopy = new ArrayList<>(refMap.values());
        for (NativeObjectRef ref : refMapCopy) {
            deleteNativeObject(rendererObject, ref.objClone, ref, true, false);
        }
        assert refMap.size() == 0;
    }
(Internal use only) Deletes all objects. 
Must only be called when display is destroyed.

@param rendererObject the renderer object
jme3-core/src/main/java/com/jme3/util/NativeObjectManager.java