Why does the JFrame setSize() method not set the size correctly?

Question

So I\'ve been programming in java for a semester or so, and I\'ve had this problem a few times and finally got around to asking.

If I make a JFrame and

Answer 1

On OS X, you need to take into account existing window decorations. They add 22 pixels to the height. So on a JFrame, you need to tell the program this:

frame.setSize(width, height + 22);