Hardly any different that having to use VTune or perf to optimise C and C++, which require the added steps of recompiling with different flags and redemploying.
I wouldn’t recommend C or C++, but in their defense, you don’t need to worry about tuning as soon as you do on the JVM. Many apps won’t need to bother with it at all (which is good because C/C++ programmers have all manner of other things to worry about that aren’t a concern for modern languages).
There's also a notion of failure mode for improperly tuned apps. This is certainly a personal preference, but I prefer true failures over constraint failures. I'd rather OOM in golang than run out of threads in my Java execution context while having plenty of free memory. At least when starting out.
Me neither, I do like Rust and see its adoption at NPM as good PR for the language, however I also think that the way the decision process went wasn't free of bias.
