Sorry, but Java isn't as fast as C++. Oh, sure, it can win some microbenchmarks, but I have yet to see an application that was as fast as C++.
In any case, the real acid test is this - an operating system. Funny, we still don't have an OS written in Java that won't take three more iterations of Moore's Law just to be useable. On the other hand, BeOS (C++) is still more responsive than my Linux desktop.