Mastering Java: The Ultimate Quiz for 'Thinking in Java'

Why does Fill2 not require a Collection as Fill did?

1. Because it uses raw types instead of generic types

2. It uses reflection to dynamically call methods

3. It only requires an implementer of an Addable interface

4. Java 8 introduced default methods in interfaces

The correct answer is: It only requires an implementer of an Addable interface

Unlike the original Fill method, Fill2 only requires an implementer of the Addable interface because it was specifically designed to work with custom objects that implement this interface. Option A is incorrect because raw types are not used in Fill2; it uses generics as well, just in a different way. Option B is incorrect because Fill2 does not use reflection, it instead relies on the methods defined in the Addable interface. Option D is incorrect because the use of default methods in interfaces is not related to the reason why Fill2 does not require a Collection.