Java is absolutely used for perf critical workloads, hell, I am fairly sure that there are no runtime in existence that would handle that load of memory pressure better - of course the problem is sort of self-made, not every allocation should have to be done in the first place in this case.

But Java is heavily used in high-frequency trading, is the backbone of many cloud infrastructures and it is such a large platform that there are plenty of small niches where it is used and performance is important.