Java generics void/Void types

Question

I am implementing a ResponseHandler for the apache HttpClient package, like so:

new ResponseHandler() {
    public int handleResponse         


        

Answer 1

Alas it's not possible. You can set the code to return Void as you say, however you can never instanciate a Void so you can't actually write a function which conforms to this specification.

Think of it as: The generic function says "this function returns something, of type X", and you can specify X but you can't change the sentence to "this function returns nothing". (I'm not sure if I agree with these semantics, but that's the way they are.)

In this case, what I always do, is just make the function return type Object, and in fact always return null.