JavaUser JavaUser - 3 months ago 25
Java Question

Final interface in Java?

Can an interface be declared as final in Java?

Answer

Interfaces are 100% abstract and the only way to create an instance of an interface is to instantiate a class that implements it. Allowing interfaces to be final is completely pointless.

EDIT The questions is not as outright outrageous as I first thought. A final interface is one that cannot be extended by other interfaces but can be implemented ostensibly makes sense.

I could think of one difference between a final class and a final interface. Extending a class can compromise its integrity because it contains some state. Extending an interface simply adds operations and cannot compromise the integrity of the implementation because the interface is stateless on its own.