[ACCEPTED]-Calling function when program exits in java-events

Accepted answer

Score: 43

You can add a shutdown hook to your application 5 by doing the following:

Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
    public void run() {
        // what you want to do
    }
}));

This is basically 4 equivalent to having a try {} finally {} block 3 around your entire program, and basically 2 encompasses what's in the finally block.

Please 1 note the caveats though!

Score: 11

Adding a shutdown hook addShutdownHook(java.lang.Thread) is probably what 4 you look for. There are problems with that 3 approach, though:

you will lose the changes if the program aborts in an uncontrolled way (i.e. if it is killed)
you will lose the changes if there are errors (permission denied, disk full, network errors)

So it might be better to 2 save settings immediately (possibly in an 1 extra thread, to avoid waiting times).

Score: 0

Are you creating a stand alone GUI app (i.e. Swing)?

If 9 so, you should consider how you are providing 8 options to your users how to exit the application. Namely, if 7 there is going to be a File menu, I would 6 expect that there will be an "Exit" menu 5 item. Also, if the user closes the last 4 window in the app, I would also expect it 3 to exit the application. In both cases, it 2 should call code that handles saving the 1 user's preferences.

Score: 0

Using Runtime.getRuntime().addShutdownHook() is 9 certainly a way to do this - but if you 8 are writing Swing applications, I strongly 7 recommend that you take a look at JSR 296 6 (Swing Application Framework)

Here's a good 5 article on the basics: http://java.sun.com/developer/technicalArticles/javase/swingappfr/.

The JSR reference 4 implementation provides the kind of features 3 that you are looking for at a higher level 2 of abstraction than adding shutdown hooks.

Here 1 is the reference implementation: https://appframework.dev.java.net/

Source: stackoverflow.com

[ACCEPTED]-Calling function when program exits in java-events

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