> I've heard that there is a new Game API for J2ME.
yes.
> Does it work on J2SE,
No, it is designed for small devices, and prob. would not be wonderfully well suited for anything more than simple side scrollers.
> or, if it doesn't, is there any
> gaming API for J2SE, or plans to do one?
A few 3rd party designed for gaming, plus you have [url http://java.sun.com/docs/books/tutorial/extra/fullscreen/index.html]Full-Screen Exclusive Mode API[/url] and Java3D (and other OGL based 3rd party extras).