Non-terminating console with JOptionPane

Question

This short program...
import javax.swing.*;
public class Test {
public static void main(String[] args) {
JOptionPane.showMessageDialog(null, "Hello!");
...running under Windows 2000 leaves the console open after the message dialog closes. I know I can terminate the program with System.exit(0), but this doesn't seem to be the "correct" approach. Some cleanup function may be required to dispose of the latent message window, but I have not found it yet. Any idea?
Thanks!

Answer 1

Hey Dan, thanks for your reply! You may be correct regarding non-terminating threads being responsible for the freeze. I have modified the test program to display running threads before and after the dialog box is shown:
import javax.swing.*;
public class Test {
public static void main(String[] args)
// Show all threads before the dialog box:
Thread[] array = new Thread[20];
int count = Thread.enumerate(array);
for (int i = 0; i < count; i++) {
System.out.println("Thread " + i + ": " + array);
System.out.println();
// Create the dialog box:
JOptionPane.showMessageDialog(null, "Hello!");
// Show all threads after the dialog box:
count = Thread.enumerate(array);
for (int i = 0; i < count; i++) {
System.out.println("Thread " + i + ": " + array[i]);
System.out.println();
Result --> there is a single "main" thread before:
Thread 0: Thread[main,5,main]
...but there are FIVE MORE threads sitting there after:
Thread 0: Thread[main,5,main]
Thread 1: Thread[AWT-Shutdown,5,main]
Thread 2: Thread[AWT-Windows,6,main]
Thread 3: Thread[Image Fetcher 0,8,main]
Thread 4: Thread[Java2D Disposer,10,main]
Thread 5: Thread[AWT-EventQueue-0,6,main]
One of these is called "AWT-Shutdown" and you would thing it would do its thing and shut down AWT but that does not happen. Another is "Java2D Disposer" and it doesn't seem to dispose of what is necessary either.
Do you have any additional insight into this situation?