Why can't you do it? What have you tried? Where exactly are you stuck?
This isn't a homework service. Show some effort.
Please elaborate -- what do you mean by "it's just not working"? Is it compiling? Are you seeing errors/exceptions? Is it misbehaving? What? Please help us help you. And what is this GUI class? It's not part of standard Java, and I doubt any of us will be able to help without knowing quite a bit more about this.