Technically Rust (and C++, IIRC) choose both, but the mindsets of most Rust(/C++) programmers/libraries is to use lower cost abstractions wherever possible. Rus

Technically Rust (and C++, IIRC) choose both, but the mindsets of most Rust(/C++) programmers/libraries is to use lower cost abstractions wherever possible. Rust provides features and libraries that provide a dynamic alternative to many different statically checked things; eg trait objects, cell types (internal mutability), shared pointers, etc. The difference is in the mindset: Most Rust programmers will hem and haw at having to use Box<Trait> until we don't have any other viable alternative (with Rust and its enums, there usually are many better ways to do it with lower cost). Java/Go libraries are completely okay with using dynamic dispatch everywhere. While writing Java code I won't be concerned about using an interface type or `Object` or whatever because zero-cost abstractions are not Java's thing. Of course, if there is a static alternative I will still prefer it, but I won't be too bothered if I just stick with `Object`.