This is an interesting project that basically targets a GPU device for executing Java bytecode. With some fairly obvious heavy limitations ...
I wont be rushing to convert any of my code over, but when I get time I will have to have a look at it. Maybe it would be useful for some prototyping - although I find JOGL a real cinch to use and I quite like C, so it might not be for me.
For doing mathematical calculations, C is simply a nicer language than Java too. With Java you're forced to use simple arrays for performance, and the lack of a primitive complex type is a real pita.
(i.e. I think I've just talked myself out of it: I also love using local memory and so on).