There's a fine line to walk when posting code. You want to post enough code for us to help you, but if you post too much code, no one will bother to read it. In your case, you posted a ton of code, but you failed to post HoyreStud or SorStud, which are obviously important pieces to this puzzle. If you did post these classes, I could practically gaurantee that noone would bother to dig through all that code. In the future, you should pare your code down to to a simple test case. One that a reader can compile and run. You'd be surprised at what you can figure out by concentrating on the problem rather than 100's of lines of code. That said, my wild guess is that HoyreStud.getRadioNr() is creating a new radio button instance with every call, so you are putting one radio button on the GUI and setting the listener on another instance.