private static String objectToString( Object o ) {
        if( o == null ) {
            return null;
        }
        String s = o + "@" + System.identityHashCode(o);
        s = s.replaceAll("\\r?\\n", "");
        return s;
    }
Debug dump to check structure and identity
jme3-examples/src/main/java/jme3test/app/TestCloneSpatial.java