Kotlin Kotlin Classes and Object-Oriented Programming 2

Question 1

How do you implement an interface in Kotlin?

Accepted Answer

Using `:` after the class name followed by the interface name

Answer

In Kotlin, both inheritance and interface implementation use the `:` syntax after the class name.

Question 2

What is the purpose of the `init` block in a Kotlin class?

Accepted Answer

To execute initialization code as part of the primary constructor

Answer

The `init` block runs initialization logic immediately after the primary constructor, in the order it appears in the class body.

Question 3

Which Kotlin feature allows a class to delegate interface implementation to another object?

Accepted Answer

Class delegation using `by`

Answer

Kotlin supports class delegation with the `by` keyword, allowing interface implementations to be forwarded to a wrapped object automatically.

Question 4

What is an object declaration in Kotlin?

Accepted Answer

A singleton object defined with the `object` keyword

Answer

An `object` declaration in Kotlin creates a singleton — a class with exactly one instance created lazily on first access.

Question 5

What does the `override` keyword do in Kotlin?

Accepted Answer

Explicitly overrides a member from a superclass or interface

Answer

`override` is required in Kotlin to explicitly mark that a member is intentionally overriding a superclass or interface member.

Kotlin Practice Test