OnJava (the O'Reilly Java portal) has a couple of articles up now that are excerpts from the Killer Game Programming in Java book. The chapter and articles they've published center around building a 3D environment. In this case, you'll build a 3D checker board and navigate around it. Java hasn't hit the level of performance you can expect from C/C++ when it comes to bit twiddling the hardware, but many games don't really need that level of complexity anyway. For those kind of games, Java is really becoming a realistic option.
ONJava.com: Killer Game Programming in Java: A 3D Checkerboard, Part 1
ONJava.com: Killer Game Programming in Java: A 3D Checkerboard, Part 2
