How Kotlin compiles to JVM bytecode - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a simple Kotlin function that returns a greeting.

Kotlin

fun greet() : String = [1]

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Aprintln("Hello, JVM!")

B"Hello, JVM!"

CHello, JVM!

Dreturn "Hello, JVM!"

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting quotes around the string

Using println instead of returning a string

The function returns the string "Hello, JVM!". It must be a string literal.

2fill in blank

medium

Complete the code to create a Kotlin class with a primary constructor that takes a name.

Kotlin

class Person(val [1]: String)

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Aname

Btitle

Cid

Dage

Attempts:

3 left

💡 Hint

Common Mistakes

Using unrelated parameter names like age or id

Forgetting to declare the parameter as val or var

The primary constructor parameter is named name to represent a person's name.

3fill in blank

hard

Fix the error in the Kotlin function that prints a message.

Kotlin

fun printMessage() {
    println([1])
}

Drag options to blanks, or click blank then click option'

AHello JVM

Bprintln("Hello JVM")

C"Hello JVM"

Dreturn "Hello JVM"

Attempts:

3 left

💡 Hint

Common Mistakes

Passing unquoted text causing syntax errors

Using return inside println

The argument to println must be a string literal, so it needs quotes.

4fill in blank

hard

Fill both blanks to create a Kotlin map comprehension that filters entries with values greater than 10.

Kotlin

val filtered = mapOf(1 to 5, 2 to 15, 3 to 20).filter { it.[1] [2] 10 }

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Avalue

B>

C<

Dkey

Attempts:

3 left

💡 Hint

Common Mistakes

Using key instead of value

Using less than operator instead of greater than

The filter checks if the value of each entry is greater than 10.

5fill in blank

hard

Fill all three blanks to create a Kotlin map from a list of words with their lengths, filtering words longer than 3 letters.

Kotlin

val words = listOf("cat", "house", "dog", "elephant")
val lengths = words.associateWith { it.[1] }
val filtered = lengths.filter { it.key.[2] [3] 3 }

Drag options to blanks, or click blank then click option'

Alength

C>

Dcount

Attempts:

3 left

💡 Hint

Common Mistakes

Using count which is a function, not a property

Using key incorrectly in associateWith

The associateWith uses it.length to get word lengths. The filter checks if the word length is greater than 3.