See here: https://jogl.dev.java.net/source/browse/jogl/doc/differences-from-gl4java.txt?rev=1.1.1.1&content-type=text/vnd.viewcvs-markup

And the user guide will give you a good overview as well: https://jogl.dev.java.net/unbranded-source/browse/*checkout*/jogl/doc/userguide/index.html?rev=HEAD&content-type=text/html

Not having used GL4Java I can't comment too much, but they seem similar on a superficial level, the more important aspects being that Jogl is still being developed while GL4Java is pretty dead by now. Jogl seems to be more up to date with new features as well.