Jvm will also use whatever libc is available, afaik. Here's an article on switching a jvm container to jemalloc from 2021. But this isn't for the heap, it's just for the jvm itself & io related concerns! https://blog.malt.engineering/java-in-k8s-how-weve-reduced-m...

Go is a rare counter example, which ignores the system allocator & bundles its own.