Kotlin Kotlin OOP 3

Question 1

What is the difference between `interface` and `abstract class` in Kotlin?

Accepted Answer

Interfaces can have default implementations; abstract classes can have state and constructors

Answer

Interfaces cannot have any implementation; abstract classes can

Answer

There is no difference

Answer

Abstract classes support multiple inheritance

Question 2

What does the `inner` keyword do when applied to a class in Kotlin?

Accepted Answer

Allows the nested class to access members of the outer class

Answer

Makes the class private

Answer

Prevents instantiation

Answer

Creates a companion object

Question 3

What is an enum class in Kotlin?

Accepted Answer

A class that represents a fixed set of constants

Answer

A class with exactly one instance

Answer

A class that cannot have methods

Answer

A sealed class with data

Question 4

Which modifier makes a class member accessible only within the same file in Kotlin?

Accepted Answer

private

Answer

internal

Answer

protected

Answer

file-private

Question 5

What is operator overloading in Kotlin?

Accepted Answer

Providing custom implementations for predefined operators using the `operator` keyword

Answer

Defining multiple functions with the same name

Answer

Overriding equals and hashCode

Answer

Implementing the Comparable interface

Question 6

What is a value class in Kotlin?

Accepted Answer

A class that wraps a single value and is inlined by the compiler to avoid object overhead

Answer

A class with only val properties

Answer

A data class with a single field

Answer

An immutable class