Kotlin Online Test

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About the test

The Kotlin online test assesses knowledge of programming in the Kotlin language and commonly used parts of the Kotlin and Java standard libraries. This test requires analyzing and understanding Kotlin code.

The assessment includes work-sample tasks such as:

  • Using OOP principles in Kotlin.
  • Working with coroutines to manage execution of code sections.
  • Understanding nullable types and infix functions.

A good Kotlin developer needs a solid understanding of the Kotlin programming language and the ability to take advantage of its features to write robust and maintainable code.

Sample public questions

3 min
Null Safety

The following Kotlin code is used in a toy drone to adjust its movement:

fun adjust(vertical: Int?, horizontal: Int?) : Unit {
    if (vertical == null) {
        println("Didn't get vertical information")
    } else {
        // Controls the drone with amplified vertical movements
        move(vertical * 2, horizontal!!)
    log_movement(vertical ?: -1, horizontal ?: -1)

Select the correct answers about the adjust function.

3 min
Infix Functions

Consider the following code used to check whether two materials are compatible to use in a construction project:

enum class Category {

data class Material (val category: Category)

// Extension infix function.
infix fun Material.compatibleWith(other: Material) : Boolean {
    return this.category == Category.LIGHT || other.category == Category.FILLER;

fun main() {
    val mat1 = Material(Category.HEAVY)
    val mat2 = Material(Category.LIGHT)
    // Use mat1 and mat2 here.

What is correct about the compatibleWith function?

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4 more premium Kotlin questions

Kilometer Converter, Meditation Application, Read First Line, Soccer Tournament.

Skills and topics tested

  • Kotlin
  • Inheritance
  • Method Overriding
  • OOP
  • Coroutines
  • Exceptions
  • Enum

For job roles

  • Back-End Developer
  • Kotlin Developer
  • Web Developer

Sample candidate report

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