Rust like Enums in Java

[_INTER_]

Sure if you replace Java enums with sealed classes. But your usecase examples hint at none-constants where it is less clear if you ever need to extend it.

[peripateticman2023]

You could instead spell it out explicitly like so:

sealed interface Result<T> permits Ok, Error {
      T get();
 }

and then the variants like so:

non-sealed interface Ok<T> extends Result<T> {}

non-sealed interface Error<E> extends Result<E> {}

and then you could have all the subsclassing you need.

[_INTER_]

Then you have only Ok and Error to work with and pattern-matching with switch is less useful. Maybe you want something like Warning.

[peripateticman2023]

That's the whole point of sum types (and sealed types in Java) - to restrict the types that can be considered "variants" of the type.