Well, I could give you a better answer if I knew which class you were having trouble reloading and how you've deployed it.
You may want to make sure that you haven't somehow included this class on the system classpath. If you have, then it gets loaded at too high a level and you can't change it without restarting WLS.
Otherwise, as long as you've only included it in your app, you should be able to change it by redeploying that app.