If you have studied the published objectives, you know that those GUI classes used in Swing are not on the exam. I don't know why people keep asking questions like this when the actual objectives are readily available at:
http://suned.sun.com/US/certification/java/exam_objectives.html#programmer I spend some time on the Swing classes in the
Java 2 Exam Prep book (not the Exam Cram) because I figured that a well rounded Java programmer should be familiar with them - also it gives me a chance to talk about Model-View-Controller
patterns and event handlers.
How best to study GridBagLayout? I'm damned if I know - I never can remember those constants. Everybody reports there is a good chance you will get a question on it though.
You should also get comfortable with Flow, Border and Grid layout managers.
Bill