Kotlin Kotlin Basics 2

Question 1

Which operator is used to perform a non-null assertion in Kotlin?

Accepted Answer

!!

Answer

The `!!` operator asserts that a nullable expression is non-null, throwing a NullPointerException if it is null.

Question 2

What is the Elvis operator in Kotlin used for?

Accepted Answer

Providing a default value when an expression is null

Answer

The Elvis operator `?:` returns the left-hand expression if it is non-null, otherwise it returns the right-hand default value.

Question 3

Which keyword is used to define a constant at the top level in Kotlin?

Accepted Answer

const val

Answer

`const val` declares a compile-time constant in Kotlin, which must be a primitive type or String at the top level or inside an object.

Question 4

What is string interpolation in Kotlin?

Accepted Answer

Embedding expressions in strings using $

Answer

Kotlin supports string interpolation using the `$` symbol to embed variables or expressions directly inside string literals.

Question 5

What does `when` replace in Kotlin compared to Java?

Accepted Answer

switch

Answer

Kotlin's `when` expression is a more powerful replacement for Java's `switch` statement, supporting arbitrary conditions.

Kotlin Practice Test