[taktoa]

Rust and C++ implement generics with monomorphization rather than boxing, so there is a potential performance hit associated with a type like this in Java that is guaranteed not to exist in Rust.

In practice, the JVM may still monomorphize it, but it is not guaranteed to, and this would be a good reason to avoid unnecessary uses of generics in a high performance codebase like a kernel, if you chose to write one in Java.

[lock1]

Sure, I guess that's worth mentioning in the context of the original post. It's true that Java implementation of parametric polymorphism has a performance drawback compared to Rust or C++. And it's certainly a bad idea to use Java generics without considering the drawback in hot code paths.

But GP described something they wanted from a type system and basically said container with `Functor`-like behavior is not possible to do in Java. It's possible, albeit with a performance drawback and a bit more clunky to work with compared to Rust, Haskell, or a language with native HKT support.

[wavemode]

the parent commenter states that Java is their everyday language, so in this context I don't think we're talking about performance, nor about the needs of the kernel.