Why won't this application terminate with DISPOSE_ON_CLOSE?

Question

I read that DISPOSE_ON_CLOSE should be used instead of EXIT_ON_CLOSE here and got confused. Does setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE) terminate the application if it has no other active threads/frames?
I landed on another question that had a link to an article that states:

DISPOSE_ON_CLOSE – Automatically hide and dispose the frame. When this is the only frame in the application the VM will also be terminated.

If my assumption that an application does terminate when it uses DISPOSE_ON_CLOSE as its value for setDefaultCloseOperation() is correct, why won't the following application terminate when I click the exit button?

Code:

public class Test extends JFrame {

  private static final long serialVersionUID = 1L;

  public static void main(String[] args) {
      SwingUtilities.invokeLater(new Runnable() {
          public void run() {
              new Test();
          }
      });
  }

  public Test() {
      super();
      setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
      setPreferredSize(new Dimension(250, 250));
      pack();
      setVisible(true);
  }
}

Update:
I am currently running Mac OS Yosemite, and java -version outputs:

java version "1.8.0_31"
Java(TM) SE Runtime Environment (build 1.8.0_31-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.31-b07, mixed mode)

I ran the program on my usual IDE (Eclipse) and on the command line, but both keep the JVM running after I close the JFrame.

*"Does setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE) terminate the application if it has no other active threads/frames?"* - Yes, which is a good way to test if there are any rouge (non-daemon) threads — MadProgrammer, May 22 '15 at 00:28
What's happening? Is it an exception, or does nothing happen? Does the frame actually close? — hyper-neutrino, May 22 '15 at 00:28
Also, your test code works fine for me (the JVM terminates after the frame is closed) — MadProgrammer, May 22 '15 at 00:29
No exception. The JFrame closes, but the application does not terminate. — goncalotomas, May 22 '15 at 00:29
And your code works fine for me with the JVM exiting as expected. — Hovercraft Full Of Eels, May 22 '15 at 00:30
I'm on Mac OS (Yosemite). Is there anyway this could be a JVM issue? — goncalotomas, May 22 '15 at 00:34
@VinceEmigh, what do you mean? I use the standard Java VM for Mac OS X. — goncalotomas, May 22 '15 at 01:21
For all we know, you could be using an implementation other than HotSpot. Which version of HotSpot are you using? Looking for possible bug reports would be easier if we knew the version. Are you using the most recent version? — Vince, May 22 '15 at 01:23
Also verified expected JVM termination after pressing the "x" button to close the frame. I'm on OS X Yosemite, using HotSpot JVM (1.7.0_75). Are you running from the command line or an IDE? — blazetopher, May 22 '15 at 03:05
Edited the question to include `java -version` output. @blazetopher, I tried both options and I'm getting the same result. — goncalotomas, May 22 '15 at 09:41
@Aprendiz do you test it with the code you posted, or do you test it with another, more complex application, that could start additional threads? — JB Nizet, May 22 '15 at 09:45

score 2 · Accepted Answer · answered May 23 '15 at 15:57

The JVM actually terminates. What happens is while the JVM exits immediately when using EXIT_ON_CLOSE, it takes up to 15 or more seconds to terminate (on my machine) when I use DISPOSE_ON_CLOSE.
I wrongfully assumed that the JVM would terminate immediately like in the first scenario, but apparently that's not the case. The minimum amount of time I had to wait was 2 seconds, but it normally takes over 5 seconds, which continuously led me to believe that it would not terminate, and I would forcefully terminate the JVM myself every time.
To me this behavior feels like its not normal, but I suppose that it would be completely transparent to a end-user, since the JFrame closes as soon as the exit button is clicked.

I have no explanation as to why using these values for setDefaultCloseOperation() is different for the JVM in such a minimal example.

Why won't this application terminate with DISPOSE_ON_CLOSE?

1 Answers1