if (killed[serverIndex]) { log.warn("Server " + serverIndex + " cannot removeNotificationListener it has been killed");  return; }
   public static void removeNotificationListener(int serverIndex, ObjectName on,                                                 NotificationListener listener) throws Exception   {      if (killed[serverIndex])      {         log.warn("Server " + serverIndex + " cannot removeNotificationListener it has been killed");                  return;      }            insureStarted(serverIndex);      if (isLocal())      {         // remove the listener directly         servers[serverIndex].removeNotificationListener(on, listener);      }      else      {         // is remote         NotificationListenerPoller p = null;         synchronized(notificationListenerPollers)         {            p = (NotificationListenerPoller)notificationListenerPollers.remove(listener);         }         if (p != null)         {            // stop the polling thread            p.stop();         }      }   }