The performance of the JVM was definitely a fair criticism in it's early years, and still is when writing performance-critical applications like databases, but it's still possibly the fastest managed runtime around, and is often only a margin slower than native code on hot paths. It seems the reputation has stuck though, to the point that I've seen young programmers make stock jokes about Java being slow when their proposed alternative is Python
Yes it's possible to write Java without any boxing of primitives or garbage collection, but one can't use any of the standard libraries and it's not really Java one is writing but a very restricted subset. I don't think these benchmark are particularly indicative of real world performance. But of course Java is still hundreds (thousands?) of times faster than Python.
It’s okay to do some allocations - it can be stack replaced, and even if it’s not, the cost is very negligible. The problem is mindless allocation, not allocation itself.
