Overwriting offset methods of ArrayObject

Hello, I just tried to overwrite a method of ArrayObject like this: class MyArrayObject extends ArrayObject {

      public function offsetGet($key)
      {
          echo "Here I am\n";
          return parent::offsetGet($key);
      }

} $o = new MyArrayObject(); $o['test'] = 'test'; echo $o['test']; I think this should output the text "Here I am" because I have overwritten the offsetGet method of ArrayObject which is called if I access an array element of this object. But it doesn't. My method is simply ignored. Then I've written a simple Object which implements the ArrayAccess interface like the ArrayObject object does. And then I have done the same as above but this time I don't extend ArrayObject but my own object. This works. My overwrite method is called I'm confused. Why can't I overwrite the method in ArrayObject? Is this a bug? Or are the methods of ArrayObject marked as "final"? But even then I must get an "Cannot override final method" error. Some hints if I misunderstood something? If not I'm going to file a bug report.