Re: Java Generics - "super" keyword usage

> So do you mean something like this:

No, I was just explaining the problem. In general it does not make
sense to have in the return type a parameter T that is not used in
the method parameters, unless it be a factory, e.g.,

   public static HashSet<T> newHashSet() { return new HashSet<T>(); }

In this case it makes sense because you tell the method you want a
something parametrized over T and it contrives to create and return
just that. In your case  you say a want a Foo<T> but you return a
Foo<X>, where all X and T have in common are that they have a common
parent. So it is your design that is the problem.

> But this causes a compiler warning.

As it should. That X and T are identical cannot be ruled out since
they both implement the same interface but it is no sure thing,
hence the warning.

Regards,

-- O.L.

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