java - Is there any relation between the class that implements interface and that interface?

Question

Consider this class hierarchy:

• Book extends Goods
• Book implements Taxable

As we know, there is a relationship between a subclass and its superclass (is-a).

Q: Is there any relationship like "is-a" between Book and Taxable?

GOOD Answers, but you said that "is-a" is also a relationship between Book and Taxable, but "is-a" is a relation between classes, and an interface is not a class!

Answer 1

Yes. The relationship is exactly the same

Book is a Taxable too.

EDIT

An interface is an artifact that happens to match Java's ( and probably C# I don't know ) interface keyword.

In OO interface is the set of operations that a class is 'committed' perform and nothing more. Is like a contract between the object class and its clients.

OO programming languages whose don't have interface keyword, still have class interface OO concept.