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

Answer 1

Book implements Taxable

Here also the relationship between Book and Taxable is

Book 'is a' Taxable

Refer this. You can see it says

When we talk about inheritance the most commonly used keyword would be extends and implements. These words would determine whether one object IS-A type of another.