Delegation vs inheritance decision in Kotlin - Quick Revision & Key Differences

Recall & Review

beginner

What is inheritance in Kotlin?

Inheritance allows a class to inherit properties and functions from a parent class, enabling code reuse and extension.

beginner

What is delegation in Kotlin?

Delegation means a class hands off some tasks to another class or object, using its functionality instead of inheriting it.

intermediate

When should you prefer delegation over inheritance?

Use delegation when you want to reuse behavior without creating a tight parent-child relationship, or when you want more flexibility and less coupling.

intermediate

What is a key downside of inheritance?

Inheritance can create tight coupling between classes, making code harder to change or extend later.

intermediate

How does Kotlin support delegation natively?

Kotlin has a special syntax called the <code>by</code> keyword that lets a class delegate implementation of an interface to another object easily.

Which keyword does Kotlin use for delegation?

A implements

B extends

C by

D delegate

Kotlin uses the 'by' keyword to delegate interface implementation to another object.

What is a main advantage of delegation over inheritance?

A Faster execution speed

B More memory usage

C Simpler syntax

D Less tight coupling between classes

Delegation reduces tight coupling, making code more flexible and easier to maintain.

Inheritance creates what kind of relationship between classes?

A Parent-child

B Peer-to-peer

C No relationship

D Delegation

Inheritance creates a parent-child relationship where the child class inherits from the parent.

When might inheritance be a better choice than delegation?

A When you want to share behavior without hierarchy

B When you want to extend or modify behavior in a clear hierarchy

C When you want to avoid tight coupling

D When you want to delegate tasks dynamically

Inheritance is good when you want a clear class hierarchy and to extend or override behavior.

Which of these is NOT a benefit of delegation?

A Tighter coupling between classes

B Avoids deep inheritance trees

C Easier to change behavior at runtime

D More flexible code reuse

Delegation reduces coupling, it does not increase it.

Explain the difference between delegation and inheritance in Kotlin and when to use each.

Think about how classes relate and share behavior.

Describe how Kotlin's 'by' keyword helps with delegation.

Focus on the language feature that makes delegation easy.