Jogre relies on binary sockets, like Arianne, Darkstar, Red dwarf, Vassal. Gamegardens looks interesting but has some weird dependencies which I want to avoid. Also, it seems to do xml parsing by hand.
Writing a gameserver indeed is not that hard. Writing a full-featured gameserver is very hard though, since it involves a lot of stuff. Think flooding, banning, rough talk detection, player admin, game admin, logging, UI elements, data definitions, et cetera. As a matter of fact, I already have a good working gameserver which can be used locally. The remote gameserver also somewhat works, but as I develop on it, most stuff I want/do just seems the 345670976542345679th wheel invented. I want to avoid that, to keep code quality high and quantity low.
Looking to most gameserver java implementations, it seems accepted to tightly couple the code to binary sockets. Which is logical, since the assumption that only java applets will consume the server was since a few years back normal. It sucks though, because it instantly rules out the possibilty to use it for my project