Also, doing a straight port from one language/platform to another is rarely intresting to look at since it usually means you won't take advantage of the new language fully.
I would only apply this to his memory-use comparison. Java has garbage collection, so it probably keeps objects around in memory for longer than his C++ implementation does. The rest of the comparsion results seem interesting to me, especially the point he makes that optimized C++ code doesn't yield better frame-rates than the Java counterpart. To me, this clearly means that game development nowadays is all about GPU, rather than CPU optimization.
Ok, maybe the point about CPU use is also invalid, since a single thread running full speed on a six-core CPU would be expected to consume 16%. He mentions ~10%, but if that's 10% of one core, or 10% of all cores is relevant too. And it also means that his tread does some waiting somewhere that might not be needed in such a comparison (since it never gets to 16%, or is that power-saving?).