如何使用Swing JPanel在Java中强制重新绘制?

Why won't my image repaint for a simple animation? I call repaint() from two different methods and one causes repaint but the other doesn't. The method that does force the repaint is generated from an event listener. The one that doesn't is a timed animation thread. I know the animation thread is running correctly, and as long as I continuously slide the slider, it displays perfectly. Help please!Why won't my image repaint for a simple animati