If a class was loaded by a ClassLoader other than the main system class loader, the class will be garbage-collected along with the ClassLoader, when there are no more references to any classes from that ClassLoader.
While you cannot unload a class, you can load a new copy of the class, using a new ClassLoader. That's what people in your situation usually do. It is not trivial to get correct, however.
Betty Rubble? Well, I would go with Betty... but I'd be thinking of Wilma.