2 frames in same VM cause problem when one frame sleeps

Question

Hi,
I need to have 2 frames within the same application. At one stage one thread needs to sleep for app. 5 seconds. During this period the other frame fail to repaint itself. I have tried lots of different things like starting the frames in different threads - but nothing work. Has even tried JDK1.5 update 5.Has anybody experienced something similiar? I've attached some code that creates 2 JFrames. One holds a label, and the other is one big button which causes a sleep. When this button is pressed the label on the other frame fail to paint.
import javax.swing.JFrame;
import java.awt.BorderLayout;
import javax.swing.JLabel;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.Frame;
import java.awt.Toolkit;
public class Main {
  public Main() {
    JFrame frame1 = new JFrame();
    frame1.getContentPane().setLayout(new BorderLayout());
    JLabel label = new JLabel("Frame 1");
    frame1.getContentPane().add(label, BorderLayout.CENTER);
    frame1.setSize(Toolkit.getDefaultToolkit().getScreenSize());
    frame1.setExtendedState(Frame.MAXIMIZED_BOTH);
    frame1.show();
    new Thread(new Runnable() {
      public void run() {
        JFrame frame2 = new JFrame();
        frame2.getContentPane().setLayout(new BorderLayout());
        JButton button = new JButton("Go to sleep");
        button.addActionListener( new ActionListener() {
          public void actionPerformed(ActionEvent e) {
            try {
              Thread.currentThread().sleep(5000);
            catch (InterruptedException ex) {
        frame2.getContentPane().add(button, BorderLayout.CENTER);
        frame2.setSize(Toolkit.getDefaultToolkit().getScreenSize());
        frame2.setExtendedState(Frame.MAXIMIZED_BOTH);
        frame2.show();
    }).start();
  public static void main(String[] args) {
    Main main1 = new Main();
}

Answer 1

You are sleeping in the Event Dispatch Thread - this will prevent all Swing events from being processed (including as you have discovered, painting).
I suggest you do some reading on the subject.
To solve your problem, you will need to thread the sleep outwith the event dispatch thread, and have your sleeping frame wait for the sleep to end before continuing (eg disable components before & re-enable after - whatever it is you need to do).
General rule of thumb - never perform time consuning work in the Event Dispatch Thread.