Having somebody else compile files over the net sounds like a big security hole to me. This server (without https, mind you) is just waiting for somebody to fiddle with DNS or routing tables to redirect careless or naive users to a trap.|
The idea is cool, though. Nicely done, though. Would be pretty fun to use if it weren't java (-;
BTW: a friend of mine has created a web-based compiler for a course he took in compiler design.