How can I exit only my sub-program, not the whole VM?

Question

I have a Java swing launcher program to launch another class (running its main method). Each program has its cancel button to exit itself.

I use System.exit(0); when this cancel button is pressed.

The launcher program does this in actionPerformed:

if (source==carMenuItem) {
    ta.append("Car launched\n");
    TestCar.main(par);

}
if (source==DialogboxMenuItem) {
    ta.append("Dialogbox launched\n");            
    DialogBox.main(par);
}        
if (source==LengthConversionMenuItem) {
    ta.append("LengthConversion launched\n");            
    LengthConversion.main(par);           
}

When I press the program's cancel button, it also closes my launcher program. How can I avoid this situation?

See my answer to [Preventing System.exit() from API](http://stackoverflow.com/questions/5401281/preventing-system-exit-from-api/5401319#5401319). — Andrew Thompson, Sep 13 '11 at 06:57

score 2 · Accepted Answer · answered Sep 13 '11 at 06:24

System.exit() terminates the VM therefore your initial thread is terminated also, simply return from your main() method.

After reviewing you code: Not all classes are supposed to have a main() method (If not also used standalone). You should consider to call a constructor to create an instance of a class and call a method not named main().

score 2 · Answer 2 · edited Sep 13 '11 at 08:06

2

Or you can use dispose() method in stead of System.exit() :-because System.exit() will terminate the total application it self.

or you can use setVisible() as false.

edited Sep 13 '11 at 08:06

Rakesh

4,264
4
32
58

answered Sep 13 '11 at 06:30

score 2 · Answer 3 · edited May 23 '17 at 11:55

2

you have to implements WindowListener and its WindowEvents, example here

another option is setDefaultCloseOperation properly

edited May 23 '17 at 11:55

Community

1
1

answered Sep 13 '11 at 06:34

mKorbel

109,525
20
134
319

score 1 · Answer 4 · answered Sep 13 '11 at 06:24

1

With System.exit you can't. This will terminate the whole JVM and all processes inside it.

answered Sep 13 '11 at 06:24

Daniel

3,019
1
20
21

How can I exit only my sub-program, not the whole VM?

4 Answers4