Stupid Cool--DOS on a Mac in a JVM?!?

I just played a game of Donkey Kong on my MacBook in a browser window that was emulating [Free] DOS through a JVM. Hu? Give it a try yourself.

I also enjoyed the FAQ section. There has been a myth for sometime now that Java is slow. Well, from the authors (Emphasis added by me.):

How fast is JPC?
...Moreover, we have seen that in some circumstances a HotSpot JVM can outperform gcc-compiled C, so we believe a lot more is possible.

Why Java?
Basically, Java turns out to be ideal for this kind of project: it's robust, it works across many platforms, it's built with security in mind and, with HotSpot, it can run about as efficiently as natively compiled code...

Take that C and C++!