import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;

public class SE3SimpleGui {

    private volatile JFrame frame;
    private volatile JButton btn;
    private volatile JTextField txt;
    private volatile Count count;
    private volatile Paint paint;
    private volatile boolean currentlyCounting;

    private void createAndShow() {
        /* Threads instanziieren */
        currentlyCounting = false;

        /* links: ein Button mit Beschriftung */
        btn = new JButton();
        btn.addActionListener(new ActionListener());
        btn.setText("Start");

        /* rechts: ein Textfeld */
        txt = new JTextField();

        /* Hauptfenster */
        frame = new JFrame();
        /* Aktion beim schließen: JVM beenden */
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        /* Layout festlegen und Button & Textfeld hinzufügen */
        frame.getContentPane().setLayout(new BoxLayout(frame.getContentPane(),
                BoxLayout.X_AXIS));
        frame.getContentPane().add(btn);
        frame.getContentPane().add(txt);

        /* Größe setzen und anzeigen */
        frame.setPreferredSize(new Dimension(300, 100));
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        /* Im EDT ausführen: new SE3SimpleGui().createAndShow(); */
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new SE3SimpleGui().createAndShow();
            }
        });
    }

    private class ActionListener implements java.awt.event.ActionListener {

        @Override
        public void actionPerformed(ActionEvent e) {
            if (!currentlyCounting) {
                btn.setText("Stop");
                count = new Count();
                paint = new Paint(count);
                count.start();
                paint.start();
            } else {
                btn.setText("Start");
                count.stopping();
                paint.stopping();
            }

            currentlyCounting = !currentlyCounting;
            frame.pack();
        }
    }

    private class Count extends Thread {

        private volatile boolean stopped = false;
        private volatile int count;

        @Override
        public void run() {
            while (!stopped) {
                count++;
            }
        }

        public void stopping() {
            this.stopped = true;
        }

    }

    private class Paint extends Thread {

        private volatile boolean stopped = false;
        private Count c;

        public Paint(Count c) {
            this.c = c;
        }

        @Override
        public void run() {
            while (!stopped) {
                txt.setText(String.valueOf(c.count));
                frame.pack();
                try {
                    Thread.sleep(500);
                } catch (InterruptedException ex) {
                    System.err.println("Error Paint");
                }
            }
        }

        public void stopping() {
            this.stopped = true;
        }

    }

}