The call System.gc() is effectively equivalent to the call:
SCJP 1.5, OCE EJB 3.x
posted 11 years ago
But if you are indeed a beginner, you should not be calling either of them. Java will do the garbage collection as necessary. You do not need to call these methods to make it happen. In fact, these methods may not do anything at all - read their documentation carefully.
Betty Rubble? Well, I would go with Betty... but I'd be thinking of Wilma.