Kotlin Kotlin OOP

Question 1

Which keyword is used to define a class in Kotlin?

Accepted Answer

class

Answer

The `class` keyword is used to define a class in Kotlin, just as in Java.

Question 2

What is a data class in Kotlin?

Accepted Answer

A class that automatically generates equals, hashCode, toString, and copy

Answer

A `data class` in Kotlin automatically generates `equals()`, `hashCode()`, `toString()`, `copy()`, and `componentN()` functions based on the primary constructor parameters.

Question 3

How do you prevent a Kotlin class from being subclassed?

Accepted Answer

Kotlin classes cannot be subclassed by default

Answer

In Kotlin, all classes are `final` by default and cannot be subclassed unless explicitly marked with `open`.

Question 4

What is a companion object in Kotlin?

Accepted Answer

A singleton object associated with a class that allows static-like members

Answer

A `companion object` is a singleton tied to a class, allowing you to define members accessible via the class name without an instance.

Question 5

Which keyword allows a Kotlin class to be inherited?

Accepted Answer

open

Answer

The `open` keyword must be added to a Kotlin class to allow it to be subclassed, since classes are final by default.

Kotlin Practice Test

Kotlin Practice Test

Kotlin Kotlin OOP