public void shutdown() {
   serverWorker.shutdownServerWorker();
 }
 public synchronized void shutdown() {
   serverWorker.shutdownServerWorker();
 }
 public void start() {
   if (!serverWorker.isRunning()) {
     new Thread(serverWorker).start();
   }
 }
 public synchronized void start() throws IOException {
   if (!serverWorker.isRunning()) {
     serverWorker.startServerWorker();
     new Thread(serverWorker).start();
   }
 }