What is the purpose of List?

Question

I didn\'t even know this was doable, but I saw while perusing some code online a method with a signature like this:

public List read( ... )
         


        

Answer 1

I agree, it's odd.

I can see a use for it if you want to extend a generic class and return void from a method. I've bumped into a case were I want to use int and had to use Integer because java generics don't like primitive types.

public interface ObjectUserPool {
    public E useObject(T o);
}

public class NonReturningObjectUserPool extends ObjectUserPool {
    public Void useObject(Integer i);
}

I think this is what the java API is saying, though to be honest I can't really find a use for NonReturningObjectUserPool.