Java thread not stopping even when while loop is done

Question

I have a client <-> server application. The problem is when I click a button "Exit" it does not kill the entire thread. It kills the process, but the thread still remains active. But if I click the "X" button the JOptionPane.showConfirmDialog is stopping everything, so I would like the button to do the same (to be terminated).

P.P. The "Exit" button starts a JSwingWorker which is calling disconnect()

@Override
public void run() {
    synchronized (this) {
        while (!serverDownAfterTry && !serverClosedByButton) {
            multicastSocket = connectToMulticastAddress(multicastIP);
            mediator = new Mediator(multicastSocket, this, objectOutput, userName);
            mediator.setSocketIP(clientSocket.getInetAddress().toString());
            mediator.setSocketPort(clientSocket.getPort());
            String input = "";
            if (connected) {
                mediator.writeOnMulticastAddress("USER_CONNECTED " + this.userName);
                mediator.executeCommands("SYSTEM_MESSAGE " + this.userName, clientGUI);
                input = mediator.listenToMultiCast(multicastSocket);
            }
            while (!multicastSocket.isClosed()) {
                input = mediator.listenToMultiCast(multicastSocket);
                if (input != null) {
                    mediator.executeCommands(input, clientGUI);
                }
            }
        }
    }
}

public void disconnect() {
    clientGUI.dispose();
    serverClosedByButton = true;
    multicastSocket.close();
    try {
        objectOutput.close();
        clientSocket.close();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

} This is what happens when i click Exit button: enter image description here

This is what happens when I click "X" button on JFrame(terminated): enter image description here

Answer 1

When you use Swing, you need to terminate your VM to exit. For example by using of System.exit(0);