If you are asking how to use stack trace to see issues, here is an example:
Running this in eclipse gives following output on console:
In your exception trace however, you do not need to check the whole trace, its verbose for most. You need to understand what causes that exception, try to fix the reason then.
The best way is to put a debug point in your code that runs well before exception occurs, and from thereon, you carefully look at whole thing at your fingertip when the debug control moves.
I have also discovered a source code link here:
http://svn.xj3d.org/xj3d_code/tags/VDST_1_1_0/src/java/org/web3d/vrml/renderer/.
Just look at DefaultNodeFactory.java in line 730 and it will be more clear to you.