Choosing Inheritance vs Composition

Choosing Inheritance vs Composition

In The Abstract Class and Inheritance, we saw how parent classes, abstract methods, overriding, and polymorphism let related classes share a common shape.

Now comes the design question interviewers love asking:

Should this class extend another class, or should it contain/use another object?

This matters because inheritance is powerful, but it also creates a tight relationship. Once a class extends another class, it inherits behavior, assumptions, and future changes from that parent.

Composition is often more flexible: instead of saying A is a B, we say A has a B or A uses a B.

By the end of this lesson, you should be able to look at a requirement and make a practical first design choice instead of forcing everything into a parent-child hierarchy.