Kotlin API

Question 1

What is Kotlin?

Answer 1

Kotlin is a statically typed programming language for the JVM, Android, JavaScript, and native.

Question 2

True or False: Kotlin is fully interoperable with Java.

Answer 2

True

Question 3

Fill in the blank: Kotlin is designed to be fully ________ with Java.

Answer 3

interoperable

Question 4

What keyword is used to declare a variable in Kotlin?

Answer 4

val for immutable and var for mutable variables.

Question 5

Which function is used to create a new instance of a class in Kotlin?

Answer 5

The constructor function.

Question 6

What does the ‘data’ keyword signify in a Kotlin class?

Answer 6

It indicates that the class is a data class, which automatically provides methods like equals(), hashCode(), and toString().

Question 7

Multiple Choice: Which of the following is NOT a valid way to declare a function in Kotlin?
A) fun myFunction()
B) function myFunction()
C) fun myFunction(param: Int)
D) fun myFunction(param1: Int, param2: String)

Answer 7

B) function myFunction()

Question 8

What is the purpose of the ‘companion object’ in Kotlin?

Answer 8

It allows you to define static members for a class.

Question 9

True or False: In Kotlin, null safety is built into the type system.

Answer 9

True

Question 10

Fill in the blank: To declare a variable that can hold null values, you append a ________ to the type.

Answer 10

?

Question 11

What is a ‘sealed class’ in Kotlin?

Answer 11

A sealed class restricts class hierarchies to a limited set of types, allowing exhaustive ‘when’ expressions.

Question 12

Multiple Choice: What does the ‘override’ keyword do in Kotlin?
A) It creates a new function.
B) It modifies an existing function.
C) It indicates that a function is implementing an interface.
D) It indicates that a function is overriding a superclass method.

Answer 12

D) It indicates that a function is overriding a superclass method.

Question 13

What is the primary use of ‘extension functions’ in Kotlin?

Answer 13

To add new functionality to existing classes without modifying their source code.

Question 14

True or False: Kotlin supports functional programming features.

Answer 14

True

Question 15

What is the difference between ‘let’ and ‘apply’ in Kotlin?

Answer 15

‘let’ is used to execute a block of code on the result of a nullable expression, while ‘apply’ is used to initialize an object.

Question 16

Fill in the blank: The ________ function is used to handle exceptions in Kotlin.

Answer 16

try-catch

Question 17

What is the purpose of the ‘inline’ keyword in Kotlin?

Answer 17

To reduce the overhead of function calls in lambdas by inlining the code at the call site.

Question 18

What is a ‘lambda expression’ in Kotlin?

Answer 18

A lambda expression is a function without a name that can be treated as a value.

Question 19

Multiple Choice: Which of the following is a valid way to create a list in Kotlin?
A) val list = List(5) { it * 2 }
B) val list = listOf(1, 2, 3)
C) val list = arrayListOf(1, 2, 3)
D) All of the above

Answer 19

D) All of the above

Question 20

What does the ‘lateinit’ modifier do in Kotlin?

Answer 20

It allows you to declare a non-null variable that will be initialized later.

Question 21

True or False: In Kotlin, you can define a function inside another function.

Answer 21

True

Question 22

What is the significance of the ‘suspend’ keyword in Kotlin?

Answer 22

It indicates that a function can be paused and resumed, making it suitable for asynchronous programming.

Question 23

Fill in the blank: The ________ function is used to launch a coroutine in Kotlin.

Answer 23

launch

Question 24

What is the purpose of the ‘withContext’ function in Kotlin coroutines?

Answer 24

It changes the context of a coroutine and is used to switch between threads.

Question 25

Multiple Choice: Which of the following is NOT a collection type in Kotlin?
A) List
B) Set
C) Map
D) Tuple

Answer 25

D) Tuple

Question 26

What is the default visibility modifier for classes in Kotlin?

Answer 26

public

Question 27

Fill in the blank: The ________ function is used to create a new coroutine scope.

Answer 27

CoroutineScope