Java pause program execution

Question

I have a method that updates part of the user interface. After this method is called I want the entire program to sleep for say 1 second. I do not want to run any code during this time, just simply pause the entire execution. What would be the best way of achieving this?

My reason is this, I am updating the GUI quite a bit and I want the user to see the change before the next change is made.

Any specific reason to do that? You can make the current thread sleep by using Thread.currentThread().sleep(), but other threads would need to get a signal for them also to sleep, if that's what you intend to do. — Vikdor, Oct 30 '12 at 02:52
What do you want the GUI to do while your program is sleeping? Should it be frozen? — Taymon, Oct 30 '12 at 02:52
Better to place your updates inside a `javax.swing.Timer`, this will allow you update the UI within a fixed time interval without "stalling" the program — MadProgrammer, Oct 30 '12 at 02:56
If you want to lock the GUI, use a `GlassPane` or `JXLayer`, pausing the EDT has more consequence then just "freezing" the UI, you can end up with out sequence repaints (the repaint manager may compress more of you updates into a single update while it's waiting for the EDT), resizing the window will not repaint properly — MadProgrammer, Oct 30 '12 at 03:08

score 1 · Accepted Answer · edited May 23 '17 at 12:03

If you want the updates to be spaced out, you've better of using something like a javax.swing.Timer. This will allow to schedule regular updates without causing the UI to look like it's crashed/hung.

enter image description here

This example will update the UI every 250 milli seconds

public class TestTimerUpdate {

    public static void main(String[] args) {
        new TestTimerUpdate();
    }

    public TestTimerUpdate() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException ex) {
                } catch (InstantiationException ex) {
                } catch (IllegalAccessException ex) {
                } catch (UnsupportedLookAndFeelException ex) {
                }

                JFrame frame = new JFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new TimerPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    protected class TimerPane extends JPanel {

        private int updates = 0;

        public TimerPane() {
            Timer timer = new Timer(250, new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    updates++;
                    repaint();
                }
            });
            timer.setRepeats(true);
            timer.setCoalesce(true);
            timer.start();
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(200, 200);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            Graphics2D g2d = (Graphics2D) g.create();
            String text = "I've being updated " + Integer.toString(updates) + " times";
            FontMetrics fm = g2d.getFontMetrics();

            int x = (getWidth() - fm.stringWidth(text)) / 2;
            int y = ((getHeight() - fm.getHeight()) / 2) + fm.getAscent();

            g2d.drawString(text, x, y);

            g2d.dispose();
        }

    }

}

You can also have a look at How can I make a clock tick? which demonstrates the same idea

Thanks for the thorough answer! – James Fazio Oct 30 '12 at 03:17 — James Fazio, Oct 30 '12 at 03:17

Java pause program execution

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