[logicchains]

>which means Java has many excellent state-of-the-art garbage collectors and a JIT a level beyond that of C#.

Unfortunately this isn't enough to make up for the latency hit from not being able to directly stack allocate things like C# allows (especially with its recent addition of Span<T>).

[chrisseaton]

> make up for the latency hit from not being able to directly stack allocate things

Java does better than direct stack allocation - it does automatic scalar replacement instead.

[logicchains]

Can automatic scalar replacement turn my ArrayList<Pair<Long, Double>> into the equivalent of std::array<std::pair<int64_t, double>, N> (or Span<Tuple<long, double>>)?

[chrisseaton]

It doesn't turn it into the equivalent of another data structure, and it doesn't allocate it on the stack, that's why it's better. It turns each value in the collection into a dataflow edge which then goes into a register, or the stack, or anywhere.

[inamiyar]

This seems really interesting, do you have any sources I can look into for more information along these lines?

[gpderetta]

so does any decent compiler. But to do that in java you first have to prove it is safe, which is hard.