Welcome, also its my personal experience that, here at JR, you'll find very few Java 3D experts, so better post your J3D queries at dev.java.net forum.
I'm very new to Java3D and i'm totally feel very vague. I don't have any idea how to use PickMouseBehavior for a ColorCube. I tried to google, but unfortunaltely i didn't get anything unseful...Please help me. Here goes my code. I tried to draw some blocks. But i want to select each block and get its co-ordinates...