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From: Knute Johnson <nospam@rabbitbrush.frazmtn.com>
Newsgroups: comp.lang.java.programmer
Subject: javax.swing.Timer blocking program termination
Date: Mon, 13 Jul 2015 16:03:53 -0700
Organization: A noiseless patient Spider
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Xref: csiph.com comp.lang.java.programmer:31994

So I have this program that uses a couple of javax.swing.Timers.  I 
forgot to put in code to stop one of the timers yet the program would 
still terminate.  I have set the default close operation for the frame 
to be DISPOSE_ON_CLOSE.

What I found was that a timer of less the 1000ms would prevent an 
application based on a JFrame from stopping but 1000ms or more and it 
would stop just fine.

I know that javax.swing.Timer uses a common thread for all timers but I 
don't see anywhere that describes the stopping behavior.

The program below will stop if the JFrame is closed and the timer is 
1000ms or greater but hang if it is less.  I would be really curious to 
know if somebody else can duplicate this.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class test extends JFrame {
     public test() {
         Timer timer = new Timer(1000,event -> {});
         setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
         setSize(400,300);
         setVisible(true);
         timer.start();
     }

     public static void main(String... args) {
         EventQueue.invokeLater(() -> new test());
     }
}

Thanks,

-- 

Knute Johnson