Java Ubuntu Linux Swing Blank Window

Question

I'm writing a Java desktop application, running Ubuntu 10.10. Everything works fine except that about 1 in 10 times, when I call JOptionPane.showMessageDialog(null, message), the dialog window appears but it is empty -- just the standard gray background. Strangely, a few times when this has happened I have been able to click where the OK button should have been and it registered the click fine. Does anyone know what could cause this?

Answer 1

Which JVM are you using? Make sure it's not GCJ (as it often is by default Ubuntu/Debian). It's swing implementation is a little odd and will often elicit strange behavior like that.

Answer 2

Are you displaying the dialog from the Event Dispatch Thread? Strange bugs with symptons like this might occur from time to time if Swings single thread rule is violated.

Answer 3

I subscribe to Uhlen's post. The most probable cause is that you might not use Event Dispatch Thread for Swing code. Example:

try {
    EventQueue.invokeAndWait(new Runnable() {
        @Override
        public void run() {
            JOptionPane.showConfirmDialog(null, "Message");
        }
    });
} catch (InterruptedException ex) {

} catch (InvocationTargetException ex) {

}