Java SystemTray with timer event

Question

I have just recently began working with the java system tray feature. In my application I have took the example from http://java.sun.com/developer/technicalArticles/J2SE/Desktop/javase6/systemtray/ for an example as to how this works.
My application also has a timer event that goes off every two seconds and checks for new messages. However if I open up the system tray popup menu, then the rest of the application hangs and waits for the pop up window to close. Is there any way to make the system tray so that the rest of the application does not freeze waiting for the menu to go away or a choice to be selected? I wold like the timer event to go off every 2 seconds, even if I have the system tray popup menu open.
Thanks for any help or suggestions.

Answer 1

Hmm. It's not that the Timer is stopped, it's that the TrayIcon displays the popup on the EDT and blocks actionPerformed -- which also has to run on the EDT -- till the popup is closed. Swing Timer by default coalesces multiple timer events when there's a backlog.
As the showing of the popup is handled by the native peer, it doesn't look like there'll be any solution with a Swing Timer. Your problem should be solvable with java.util.Timer and TimerTask.
Try this code, then uncomment the setCoalesce(false) and try it again. Note the difference.import java.awt.AWTException;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.MenuItem;
import java.awt.PopupMenu;
import java.awt.SystemTray;
import java.awt.TrayIcon;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
public class TrayIconTest {
   public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
         @Override
         public void run() {
            new TrayIconTest().makeUI();
   public void makeUI() {
      PopupMenu popup = new PopupMenu();
      popup.add(new MenuItem("One"));
      popup.add(new MenuItem("Two"));
      TrayIcon trayIcon = new TrayIcon(getImage(), null, popup);
      try {
         SystemTray.getSystemTray().add(trayIcon);
      } catch (AWTException ex) {
         ex.printStackTrace();
      JFrame frame = new JFrame();
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.setSize(200, 200);
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
      javax.swing.Timer swingTimer = new javax.swing.Timer(1000, new ActionListener() {
         int count = 0;
         @Override
         public void actionPerformed(ActionEvent e) {
            System.out.println("Swing Count: " + count++);
      //swingTimer.setCoalesce(false);
      swingTimer.start();
      java.util.TimerTask timerTask = new java.util.TimerTask() {
         int count = 0;
         @Override
         public void run() {
            System.out.println("Util Count: " + count++);
      java.util.Timer utilTimer = new java.util.Timer();
      utilTimer.scheduleAtFixedRate(timerTask, 1200, 1000);
   private Image getImage() {
      BufferedImage image = new BufferedImage(16, 16,
            BufferedImage.TYPE_INT_ARGB);
      Graphics2D g2 = image.createGraphics();
      g2.setColor(Color.RED);
      g2.fillOval(1, 1, 14, 14);
      g2.setColor(Color.YELLOW);
      g2.fillOval(5, 5, 6, 6);
      return image;
}db