JFrame.dispose not closing frame

Question

My program will not close the specified frame in some cases. For some reason it will close fine when ran through IntelliJ using the run command, but after compiling into a jar and wrapping with Launch4J it gets stuck when I try to close it programmatically. Here is the applicable code:

Classic.java

import javax.swing.*;
import java.io.FileNotFoundException;
import java.io.PrintStream;
import java.util.*;
import java.text.SimpleDateFormat;
import static javax.swing.SwingUtilities.invokeLater;
public class Classic extends Game{
    private static JFrame gui;
...
    //Starts game and opens gui
    public void play() {
        invokeLater(Classic::startGUI);
        //startGUI() intiates gui correctly, let me know if you need it
        new Thread(Classic::startGame).start();
    }
...
    public static void startGame() {
        //Program works fine until closing window;
        //Game methods and code omitted
        print("Thank you for playing!" + System.lineSeparator() + "Press enter to exit.");
        boolean end = false;
        while (!end) {
            //isInputReady() checks if user pressed enter
            end = newContentPane.isInputReady();
        }
        gui.dispose();
    }
}

I'm not sure if this is a code error or an error with Launch4J since this only occurs in the Launch4J compiled version (not through IntelliJ or via java.exe -jar).

EDIT: I also tried killing the GUI thread with thread.interrupt(), but that didn't change the outcome.

... I thought it closes after the code reaches the end of the method. I don't have an explicit thread closer. — greatmastermario, Jan 14 '16 at 02:57

score 0 · Answer 1 · edited May 23 '17 at 12:23

0

You can try gui.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE); (set this option after instantiating the gui object)

Normally, a JVM closes after every non-deamon thread reaches its end. Swing creates its own thread for handling events (EDT). I assume that in your application in certain cases a non-deamon thread is still running which prevents the JVM from closing.

You can find additional information in this thread: JFrame.dispose() vs System.exit()

edited May 23 '17 at 12:23

Community

1
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answered Jan 14 '16 at 09:29

morpheus05

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The reason I was using JFrame.dispose() was to only close the window. The game code above is started through a separate menu, but I don't want the menu to close at the end of the game. Also as stated above, it works fine when ran through IntelliJ or as a Jar, but compiling it with Launch4J causes the issue. – greatmastermario Jan 14 '16 at 23:11
The fact remains, that a after you wish to close the application, a thread is still running so you only have to option: For the VM to exit with System.exit() which is not that great or check which Threads are still running. Use the Thread-API to access all threads and print them to the console. Then you see the difference from IDE to Launch4j. – morpheus05 Jan 15 '16 at 08:57
When I am looking for the thread, do I look in the JVM threads or somewhere else? It shouldn't have anything to with the JVM since it has the correct behavior in IntelliJ and as a Jar. Launch4J is not a part of a program, it is just a wrapper to run it as a Windows executable. Does it have separate thread handling from the JVM in this case? Also, I am not trying to close the whole program, just the window. The game (shown above) opens in a separate window from the options, which stay open so you can start a new game after you finish. – greatmastermario Jan 25 '16 at 16:29

JFrame.dispose not closing frame

1 Answers1