I had a closer look on both. They seem to be relatively general in terms of covered topics and languages. You mentioned that already... But yeah thanks anyway! Do you visit them regularly?
the USF yes: I receive an e-mail everyday with the new and updated topics in the programming board, which almost never more the 2 or 3 topics. if one is interesting to me, I read it and possibly post.
I am actually looking for a way to promote FengGUI in the German Java game dev community. But I suppose people who are serious about gaming in Java know www.java-gaming.org
Yes, JGO is THE java gaming forum and where your promotiom probably has the most impact. But since its a graphical project, why not make a nice looking GUI and submit it to various IOTD pages (gamedev.net, softgames.de, .)? Or have you done that already?