Objects.requireNonNull() shows zero overhead here.
I guess the main question is whether Objects.requireNonNull(this)
behavior in the former test is a result of chance and current Hotspot
behavior or is it somehow guaranteed by the spec.
I haven't looked into what actually happens in JIT-compilers on your
benchmark, but I'm surprised it works at all.
Explicit null check on the receiver is an easy target for elimination
and should be effectively a no-op in generated code. (And that's what
you observe with the benchmark!) Once the check is gone, nothing keeps
receiver alive anymore (past the last usage).
So, I'd say such behavior it's a matter of chance in your case and can't
be relied on in general. And definitely not something guaranteed by JVMS.
Best regards,
Vladimir Ivanov
