> A short fact about .NET: if you have an interface IFoo<T>, the runtime generates a separate method table per each IFoo<int>, IFoo<double>, IFoo<bool>, and so

> A short fact about .NET: if you have an interface IFoo<T>, the runtime generates a separate method table per each IFoo<int>, IFoo<double>, IFoo<bool>, and so on. In Java you have to do the same manually: https://docs.oracle.com/javase/8/docs/api/java/util/stream/Stream.html#mapToInt-java.util.function.ToIntFunction- https://docs.oracle.com/javase/8/docs/api/java/util/stream/S... wow such polymorphism much ad-hoc