I’ve never heard of JPC before. It is an x86 PC emulator written in pure Java. Of course, as all the applications written in Java it runs in the VM and therefore it doesn’t depend on the platform. That’s a big advantage over other emulators written in C++.
One of the main concerns about emulators (and also Java) is the performance. I was surprised how JPC has been tuned to have such a very good performance. Also, minimal security risk is provided since the emulation is isolated inside of the VM.
I’m thinking of giving JPC a deep look and maybe to try it out. In the next months we could see this emulator becoming very popular.