public void stop(){
  if (running) {
    running=false;
    thread.interrupt();
    if (!server.isClosed()) {
      server.close();
    }
  }
}

public void stop ( ) { if ( running ) { running = false ; thread . interrupt ( ) ; if ( ! server . isClosed ( ) ) { server . close ( ) ; } } }
stop the udp relay server .
