Working on LLG, I found that the very simple game was able to saturate the Java2D graphics pipeline. So much time was spent rendering that too little remained for adding more interesting game features.
As a result, I started FV3DS and FV3TK as a launch into the JOGL-2/NEWT graphics.
JOGL-2/NEWT is very interesting. NEWT is a complete replacement for the AWT! For me, that's hot. To see what I know about JOGL-2/NEWT, have a read through FV3TK.