I'm currently developing a Java App. And I need to add and remove
functionality from standaard Swing Components. Plus, in some cases,
like the JScrollBar's, I need to give them a different look. Now I've
looked in the tutorials, but they mostly refer to a lot of x.set...()
functions, which just isn't sufficient for my needs. And I've looked
through the source files of various components, but that just gives
me the impression that most of the values pop out of nowhere :)

So, my question: How do you *really* customize a Java Component?
Like for instance, give the JScrollBar a different look, give the
JFrame a different shape, etc, stuff in that area.