my question is simple. How to force JAVA to terminate the program I am writing when any Exception occures?

I am currenlty using Swing and when a NullPointer exception is thrown, the program keeps on running in the background :| While running this way I can only close it from the task manager. The bad thing is that when I run the same program again, a second instance is created and I don't know why, but when I have more than 1 instance of the same program, one time I get null exception, next time not, next time yes, next time not.... Complete randomness.

Thanks in advance!