Java equivalent of .NET Action<T> and Func<T,U>, etc [duplicate]

Question

Are there any standard generic "callback" or "function/method" types in Java, like System.Action<T> or System.Func<T,U> in .NET?

In my concrete case, I need a class that wraps a method that takes one (generic) parameter of type T and returns nothing (i.e. void).

Yes, it's easy enough to create such a class/interface for myself, but I'd prefer a standard library class if there is one.

Answer 1

I don't believe there's anything in the standard library like this, no (at the time of writing, 2010). Other libraries have them - things like Guice's Provider<T> and Guava's Function<F, T>, Supplier<T> and Predicate<T>... so if you're using libraries already, you might want to look into what they provide in this direction.

(EDIT: As noted, those are interfaces which return things - so similar to Func<T, U> but not similar to Action<T>.)

Answer 2

Java standard library doesn't provide any such classes.

You can use Functional Java library which provides fj.F1<T, fj.Unit> which is basically equivalent of System.Action<T> from .NET.