Set ckeys = cancelledKeys ();
Set<SelectionKey> ckeys = cancelledKeys ();
  private final void deregisterCancelledKeys()  {    Set ckeys = cancelledKeys ();    synchronized (ckeys)    {      Iterator it = ckeys.iterator();      while (it.hasNext ())        {          keys.remove ((SelectionKeyImpl) it.next ());          it.remove ();        }    }  }