It would've been nice if you at least said what link :-) Almost all of the linked tutorials have been published by persons that the jogamp maintainers have no contact with. Try asking the person that published the linked tutorial.
Re: Learning about JOGL and OpenGL from Java3D background.
The latest released version is 2.3.2, the next maintenance version will be 2.3.3.
Some tutorials not stored into our server might have become unreachable, there is nothing we can do but there are tons of other tutorials that are still available.
By the way, Java3D 1.5.2 is no longer maintained, we maintain only Java3D 1.6.0-final and mainly Java3D 1.7.0.
JOGL and OpenGL entry points are very similar, we provide higher level APIs too but you can still use low level APIs anyway. I advise you to have a look at our Java API documentation. xerxes and me provided some examples for OpenGL and OpenGL ES 1 & 2, elect provided more modern examples, jogl-demos on Github contains our demos, all examples of the OpenGL Red Book have been translated to JOGL.