I implemented a bouncing ball in Java using JOGL, Sun's OpenGL binding.
The graphics are only 2D, but they are hardware accelerated (when possible), and could easily be made 3D.
A major goal of my work was serving the Java application so that it runs immediately on any platform, without requiring JOGL to be previously installed. This is made possible by Java Web Start, which I instruct to download the appropriate native library for the user's platform. The supported platforms are Mac, Windows, Linux, and Solaris.
Click to run: Bouncing Ball
Things to try: