Here is some more information pertaining to J3D:
There is program reading and viewing the format. It is called 3D Object Converter and it can be found here:
http://3doc.i3dconverter.com/
It can only read the format and you need to register it to be able to save to other formats (but not J3D).
To be able to save to J3D one needs plugin which works only with old 3dsMax3.1 and in its original form has pretty low vertex limitation for models (can be hacked I think).