> Most probably their Java code was FUBAR.

And so what? If a language's natural form leads to FUBAR code, what else is to blame?

Really? You can write FUBAR code in any language, language has nothing to do with this.

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.

Nice false premise there. It could easily be caused by other things.