The title is link bait to the point of nearly trolling. He didn't do his research, he should have jumped on the Google group or Stack overflow or something before writing this. Someone named Mike in the comments on the OP comes up with a fix that uses Java primitives and that is very fast, in the range of his Lush examples.

http://scottlocklin.wordpress.com/2011/11/30/only-fast-langu...

There's almost nothing to see here, except maybe that there should be better documentation on this kind of optimization.