Fair enough, I personally don't have first hand experience with the super tight loop stuff on the JVM (though that seems like it'd be fun!). The JVM has always been fast enough for MY needs, but I realize that's not true for everyone. Thanks for the link, that seems like a good mailing list.
Nah I mean this stuff IS hard. That's why I offered that mailing list. Like I said a lot of people from azul and a lot of the hardcore jvm heads sit on there.
If there's a way to make java faster for that great. You are are right that the jvm DOES support some of the tight loop stuff.
It's harder to do and leads to messy code though. In C++ you can write maintainable code and add pragmas. It's a lot cleaner and with javacpp (https://github.com/bytedeco/javacpp) we just generate the jni bindings.
We found that to be easier in practice. I'm admittedly not THAT familiar with the jvm internals.
I have just tried to get it to work and have did enough reading to know jni will just be cleaner for that stuff.
The JVM is certainly fast enough, just mainly for distributed systems code (eg: databases, message queues)
Honestly that's what makes it appealing for me. I can write fast production systems and tweak it where necessary for the HPC apps.
Java provides a fast and safe baseline for 90% of the stuff I'd want it to do. We tried for about a year to get it to work for lin alg and finally said screw it let's just do c++.
