Question

I have a Java application that uses swing. I have found a way to catch all uncaught exception in an application (see below). I would like to log a message, show a dialog with a message for the user and kill the application. The problem is, what I’m trying to catch are some swing exceptions. Trying to show a dialog after the exception is caught in the UncaughtExceptionHandler is impossible since the Swing thread is stopped. Is there any way to then show a dialog? Creating a new swing thread or something like this?

Thanks!

Thread.setDefaultUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {
    boolean alreadyCaught = false;

    public void uncaughtException(Thread t, Throwable e) {
        if (alreadyCaught)
            return;

        alreadyCaught = true;
        e.printStackTrace();

        //show Dialog
    }
});

Answer 1

It is perfectly possible to show a dialog from the default uncaught exception handler. One of our products is using this mechanism for the last 5 years without any problems.

We have a workaround for the problem when the EDT is being replaced due to the exception killing the current EDT. Instead of using the regular SwingUtilities#invokeLater to show the dialog, we use

new Thread( new Runnable() {
      public void run() {
        EventQueue.invokeLater( aRunnable );
      }
    } ).start();

This allows the EDT to be replaced by a new one, and runs the Runnable on the newly created EDT.