Coroutines vs threads mental model in Kotlin - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

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

Kotlin

GlobalScope.[1] {
    println("Hello")
}

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

ArunBlocking

Basync

Claunch

Ddelay

Attempts:

3 left

💡 Hint

Common Mistakes

Using runBlocking inside GlobalScope.launch which blocks the thread.

Using delay as a coroutine builder which is incorrect.

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

2fill in blank

medium

Complete the code to block the main thread until the coroutine finishes.

Kotlin

runBlocking [1] {
    launch {
        println("Running in coroutine")
    }
}

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

A{

B() -> Unit

C{ }

Dasync

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses instead of curly braces for the lambda block.

Trying to use async as a parameter to runBlocking.

The runBlocking function takes a lambda block enclosed in curly braces { } to run coroutine code and block the thread.

3fill in blank

hard

Fix the error in the code to correctly start a thread that prints "Thread running".

Kotlin

val thread = Thread [1] {
    println("Thread running")
}
thread.start()

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

A{

B() -> Unit

C()

Drun

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses instead of curly braces for the lambda.

Passing a function type instead of a lambda block.

The Thread constructor takes a lambda block enclosed in curly braces { } to define the thread's work.

4fill in blank

hard

Fill both blanks to create a coroutine that delays for 1000ms and then prints "Done".

Kotlin

GlobalScope.[1] {
    delay([2])
    println("Done")
}

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

Alaunch

B1000L

C500

DrunBlocking

Attempts:

3 left

💡 Hint

Common Mistakes

Using runBlocking instead of launch.

Using 500 instead of 1000L for delay.

The launch builder starts the coroutine, and delay(1000L) pauses it for 1000 milliseconds.

5fill in blank

hard

Fill all three blanks to create a map of coroutine names to their status checking if they are active.

Kotlin

val coroutinesStatus = mapOf(
    "coroutine1" to [1],
    "coroutine2" to [2],
    "coroutine3" to [3]
)

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

Ajob1.isActive

Bjob2.isActive

Cjob3.isActive

Djob4.isActive

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same job variable multiple times.

Using a job variable that is not declared.

Each coroutine job has an isActive property to check if it is still running.