Nice project. One thing I would focus on is allowing for a zero litter work flow. In Hazelcast I wrote a similar system, and if properly used, it is litter free.

The GC can pace the allocation when it can't keep up.

If a Java thread is on the CPU, then the CPU is utilized, no matter if the CPU is just waiting for memory.

That is the problem with utilization; you have no clue how busy the CPU actually is. IPC is more useful in these situations.