[adra]

I'm pretty sure the exercise was to show the absolute extremes that could be achieved in a toy application and possibly how easy one could achieve some level of IO blocking scaling that has been harder than most other tasks in java of late. More and more, heap allocations are cheaper, often with sub-milli collector locks, CPU scaling has more to do with what you're doing instead of the platform, but java have enough tools to make your application fast.

For extremely IO wait bound workloads though, there was always a LOT if hoops to jump through to make performance strong since OS threads always have a notable stack memory footprint that just doesn't scale well when you could have thousands of OS threads waiting around just taking up RAM.