Java: block memory allocator?

Question

Java

Is there any possibility in Java to create a block memory allocator ?
Initially I thought to do it through JNI, but you can’t return the pointer from there to allocate memory, you can’t give it back to deallocate.

At the same time, there are applications written in languages ​​that have a GC that would never work properly without a custom allocator. So the developers of these applications somehow solved this issue

Answer 1

https://docs.oracle.com/javase/8/docs/api/java/nio...