why my code “Bouncing ball” doesn't work?

Question

I\'m trying to write a code a bout a bouncing ball, but i\'m stuck in how to make the ball bounced. The code seems correct, no wrong messages from eclipse and yet the ball d

Answer 1

private Timer timer = new Timer(20, new TimerListener());

doesn't that new TimerListener() need to do something useful? shouldn't most of the code inside StartBouncingBallTest be happening every time the timer ticks, intsead of just once when the timer starts?