How to stop a thread which is waiting for a client socket connection?

[Short answer: you can't stop the thread, but you can close the socket, which causes accept to return. -Alex]

Hope that I've understood you properly. So I assume, that you've got something like:

public class MyServer extends Thread  {

  // ...
  private ServerSocket waitingSocket  = null;
  // ...

  public void run() {
    // ...

    waitingSocket = new ServerSocket( serverSocketPortNumber );

    while( yourAlwaysTrueCondition ) {

      connectionSocket  = waitingSocket.accept();

      delegateInteractionWithClient( connectionSocket );

    }
    // ...
  }
}

• possibility to call server for shutting down (shutdown() method)
• end of waiting for incomming client connections (will be an if statement in your while loop)

public class MyServer extends Thread  {

  // ...
  private ServerSocket waitingSocket  = null;
  // ...
  private boolean shutdownRequested   = false;

  public void run() {
    // ...

    waitingSocket = new ServerSocket( serverSocketPortNumber );

    while( yourAlwaysTrueCondition ) {

      connectionSocket  = waitingSocket.accept()

      if( shutdownRequested==false )  {
        delegateInteractionWithClient( connectionSocket );
      }
      else  {
	break;
      }

    }
    // ...
  }

  public void shutdown()  {

    shutdownRequested = true;

    new Socket(
      waitingSocket.getInetAddress(),waitingSocket.getLocalPort()
      ).close();
  }
}