Concept of functional interface

Question

When I\'m shooting a glance at lambda expressions, the book touches on a functional interface that has only one abstract method. My issue addresses on that quiz que

Answer 1

interface SmartAdder overloads, not overrides interface Adder. That's because the name is the same name, but parameters types are different. Therefore, it has 2 functions. To be a functional interface it needs to have only one function.

==> Only interface Adder is a functional interface.