Modifier Keywords & Special Identifiers

Question 1

actual

Answer 1

denotes a platform-specific implementation in multiplatform projects

Question 2

abstract

Answer 2

marks a class or member as abstract

Question 3

annotation

Answer 3

declares an annotation class

Question 4

companion

Answer 4

declares a companion object

Question 5

const

Answer 5

marks a property as a compile-time constant

Question 6

crossinline

Answer 6

forbids non-local returns in a lambda passed to an inline function

Question 7

data

Answer 7

instructs the compiler to generate canonical members for a class

Question 8

enum

Answer 8

declares an enumeration

Question 9

expect

Answer 9

marks a declaration as platform-specific, expecting an implementation in platform modules

Question 10

external

Answer 10

marks a declaration as implemented not in Kotlin (accessible through JNI or in JavaScript).

Question 11

final

Answer 11

forbids overriding a member

Question 12

infix

Answer 12

allows calling a function in infix notation

Question 13

inline

Answer 13

tells the compiler to inline the function and the lambdas passed to it at the call site

Question 14

inner

Answer 14

allows referring to the outer class instance from a nested class

Question 15

internal

Answer 15

marks a declaration as visible in the current module

Question 16

lateinit

Answer 16

allows initializing a non-null property outside of a constructor

Question 17

noinline

Answer 17

turns off inlining of a lambda passed to an inline function

Question 18

open

Answer 18

allows subclassing a class or overriding a member

Question 19

operator

Answer 19

marks a function as overloading an operator or implementing a convention

Question 20

out

Answer 20

marks a type parameter as covariant

Question 21

override

Answer 21

marks a member as an override of a superclass member

Question 22

private

Answer 22

marks a declaration as visible in the current class or file

Question 23

protected

Answer 23

marks a declaration as visible in the current class and its subclasses

Question 24

public

Answer 24

marks a declaration as visible anywhere

Question 25

reified

Answer 25

marks a type parameter of an inline function as accessible at runtime

Question 26

sealed

Answer 26

declares a sealed class (a class with restricted subclassing)

Question 27

suspend

Answer 27

marks a function or lambda as suspending (usable as a coroutine)

Question 28

tailrec

Answer 28

marks a function as tail-recursive (allowing the compiler to replace recursion with iteration)

Question 29

vararg

Answer 29

allows passing a variable number of arguments for a parameter

Question 30

field

Answer 30

is used inside a property accessor to refer to the backing field of the property

Question 31

it

Answer 31

is used inside a lambda to refer to its parameter implicitly