[vardump]

Allocation heavy C++ can be pretty slow. It's also true unoptimizable (pure) virtual methods performing little work have quite a bit overhead that JVM can avoid.

Of course you normally try to avoid writing C++ like that.

[pkolaczk]

Allocation heavy Java is also very slow. But it is much easier to avoid heap allocations (and virtual calls!) in C++/Rust than in Java.

[pjmlp]

For the time being, I still hope that Valhalla will eventually make it.