Java JFrame & JPanel Differences with Repaint()

Question

I have been playing about with some simple painting of Graphics2D and have some extremely good help from the community here.

I managed to get the flickering resolved from my "bouncy balls" by moving the code away from the main JFrame class and into a JPanel which I then added to the JFrame class, can anyone tell me why this would make such a difference?

Answer 1

When you draw in a JComponent's paintComponent method (such as a JPanel's), you use Swing which uses double-buffering when drawing by default. Drawing directly in a JFrame's paint method will only allow AWT type drawing since the JFrame directly inherits from Frame, a heavy weight container, and since AWT graphics does not use double buffering by default and this will lead to choppy animation.