If you ever wanted to create 3d apps or 3d games, add didn't knew where to start, you will be happy to know that you can do that and a lot more with Java 3D.
Java 3D API is an extenstion to the JDK, you can find info about downloading the API & it's documents , and a lot of Tutorials to get started at
http://www.j3d.org .
Or check the sun's site at
http://java.sun.com.
if you want to ask me a question just email me! ;D