protected void accept_loop() {
   while (isRunning()) {
     try {
       SocketChannel client_channel = server_channel.accept();
       last_accept_time = SystemTime.getCurrentTime();
       client_channel.configureBlocking(false);
       listener.newConnectionAccepted(server_channel, client_channel);
     } catch (AsynchronousCloseException e) {
       /* is thrown when stop() is called */
     } catch (Throwable t) {
       Debug.out(t);
       try {
         Thread.sleep(500);
       } catch (Exception e) {
         e.printStackTrace();
       }
     }
   }
 }