The "No Waste Compute" Constraint
When I started designing the Exeris Kernel, I set one non-negotiable rule very early: no waste compute. That rule sounds like a performance slogan until it starts killing otherwise normal design decisions.
I had already banned ThreadLocal , moved context propagation to Scoped Values, and pushed more of the runtime into explicit off-heap ownership. The idea was simple: if the hot path is supposed to stay outside GC pressure, then memory shape and lifetime cannot be treated as incidental details.
Then I reached TLS.
Constraint upfront: this is not a universal argument against SSLEngine . For a normal Java service it is still a perfectly reasonable choice — battle-tested and deeply integrated into the ecosystem.…