Of course you can. But if the same developers write performant code in one language, and something really slow in another, that's a mark against the second language. Maybe there's a tradeoff - maybe the slow codebase was written much faster, or something like that. But the kind of code a language makes you write is totally something you should judge it on.

Well i am quite experienced with Java and in my experience if they have this kind of ridiculous discrepancy in memory use, it implies they had a bad design or made bad choices. A rewrite in Java with sane choices would also end up with much better results. So I don't buy the "language is responsible" argument.