Iterator it = warningListeners.iterator();
if (warning == null) throw new IllegalArgumentException ("null argument"); if (warningListeners != null) { Iterator it = warningListeners.iterator();
  protected void processWarningOccurred(String warning)  {    Iterator it = warningListeners.iterator();    while (it.hasNext())      {	IIOReadWarningListener listener = (IIOReadWarningListener) it.next();	listener.warningOccurred(this, warning);      }  }