Try a
Java decompiler such as Mocha or Crema. Decompile your class into source code and comment it again.
You can get a free version of an old beta of Mocha from
http://www.brouhaha.com/~eric/computers/mocha.html. This is probably enough for retrieving your deleted .java file. Of course you could also buy a commercial decompiler of which there are quite a few.
Good luck.