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

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 开发者_如何学运维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?

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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().

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you have to implements WindowListener and its WindowEvents, example here

another option is setDefaultCloseOperation properly

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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.

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