GapContentPosition pos = (GapContentPosition) i.next();
WeakReference r = (WeakReference) i.next(); GapContentPosition pos = (GapContentPosition) r.get();
  private void dumpPositions()  {    for (Iterator i = positions.iterator(); i.hasNext();)      {        GapContentPosition pos = (GapContentPosition) i.next();        System.err.println("position at: " + pos.mark);      }  }