Launch coroutine builder in Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to launch a coroutine that prints "Hello".

Kotlin

import kotlinx.coroutines.*

fun main() = runBlocking {
    [1] {
        println("Hello")
    }
}

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Adelay

Basync

Crun

Dlaunch

Attempts:

3 left

💡 Hint

Common Mistakes

Using async instead of launch when no result is needed.

Trying to call delay directly without a coroutine builder.

The launch builder starts a new coroutine without blocking the current thread.

2fill in blank

medium

Complete the code to launch a coroutine that delays for 1000ms before printing "Done".

Kotlin

import kotlinx.coroutines.*

fun main() = runBlocking {
    launch {
        [1](1000)
        println("Done")
    }
}

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Await

Bdelay

Cpause

Dsleep

Attempts:

3 left

💡 Hint

Common Mistakes

Using Thread.sleep which blocks the thread instead of suspending the coroutine.

Using incorrect function names like wait or pause.

The delay function suspends the coroutine without blocking the thread.

3fill in blank

hard

Fix the error in the code to correctly launch a coroutine inside runBlocking.

Kotlin

import kotlinx.coroutines.*

fun main() = runBlocking {
    [1] {
        println("Inside coroutine")
    }
}

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Alaunch

Brun

Casync

DcoroutineScope

Attempts:

3 left

💡 Hint

Common Mistakes

Using run which is not a coroutine builder.

Using coroutineScope without proper context.

The launch builder is the correct way to start a coroutine inside runBlocking.

4fill in blank

hard

Fill both blanks to launch a coroutine that prints the thread name.

Kotlin

import kotlinx.coroutines.*

fun main() = runBlocking {
    [1] {
        println("Running on: " + Thread.[2]().name)
    }
}

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Alaunch

BcurrentThread

CmainThread

Dasync

Attempts:

3 left

💡 Hint

Common Mistakes

Using mainThread which does not exist.

Using async when no result is needed.

launch starts the coroutine, and Thread.currentThread gets the current thread.

5fill in blank

hard

Fill all three blanks to launch a coroutine that delays and then prints a message with the delay time.

Kotlin

import kotlinx.coroutines.*

fun main() = runBlocking {
    val time = 500L
    [1] {
        [2](time)
        println("Waited for [3] ms")
    }
}

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

Alaunch

Bdelay

Ctime

Dasync

Attempts:

3 left

💡 Hint

Common Mistakes

Using async instead of launch when no result is needed.

Using a literal number instead of the variable time in the print statement.

launch starts the coroutine, delay suspends it, and time is the variable holding the delay duration.