JTextArea在多线程中不起作用-Java

Question

I have a code that updates the JTextArea in run() method.

But when run method executes the append() method is not executed.

It prints the currect value of incomingMessage variable but not gets append to the JTextArea .

public void run()
{

    while (true)
    {
        try
        {
            if(serverSocketMessage==null)
            {
                serverSocketMessage = new ServerSocket(Constants.INCOMING_MESSAGE_PORT);
            }
            System.out.println("Listening to incoming messages");

            ObjectInputStream objectInputSender;
            String incomingMessage = null;

            serverMessage = serverSocketMessage.accept();
            objectInputSender = new ObjectInputStream(serverMessage.getInputStream());
            Object objectMessage = objectInputSender.readObject();
            if (objectMessage instanceof String)
            {
                incomingMessage = objectMessage.toString();
                System.out.println("\nMessage\n"+incomingMessage);
                if(incomingMessage!= null)
                {
                    chatingJTextArea.append(incomingMessage);
                    System.out.println("Not null");
                }

                chatingJTextArea.append("\n");
                chatingJTextArea.append(incomingMessage);



            }
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }

    }

Answer 1

Try invoking append in the EDT

private void addMessage(final String message) {
    SwingUtilities.invokeLater(new Runnable() {

        @Override
        public void run() {
            chatingJTextArea.append(message);

        }
    });
}

Answer 2

A solution would be to implement the processing using a SwingWorker. The doInBackground method would implement the processing and you would invoke the publish method with the String to be appended as the argument. Your SwingWorker would then override the process method to take a String argument and append it to the text area.

I don't have enough privilege to make this a comment but I removed the thing you said is wrong.