Retrieving type parameters from an instance of a generic base interface

Question

Given 2 interfaces:

public interface BaseInterface { }
public interface ExtendedInterface extends BaseInterface {}
         


        

Answer 1

I don't think there's an direct way of getting the generic type of the base interface.

One way would be to declare a method in the interface like this:

public interface BaseInterface {
    Class getGenericClass();
}

Also, I don't know what kind of control you have over these classes. You can always assert that all implementers have the base interface explicitly declared like:

public class MyClass implements ExtendedInterface, BaseInterface{ }

and

MyClass.class.getGenericInterfaces()[1].getActualTypeArguments()[0]