This week's book giveaway is in the Mac OS forum. We're giving away four copies of a choice of "Take Control of Upgrading to Yosemite" or "Take Control of Automating Your Mac" and have Joe Kissell on-line! See this thread for details.
There are 2 distinct variables named spelarJB -- one is a member, shared by all methods, the other declared in the createGUI() method. This latter one is the one being initialized, but your event handler is expecting the former one to be. In CreateGUI, don't say "JButton spelarJB =" -- just say "spelarJB =". This is a common mistake!