CancellationException behavior in Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to catch a CancellationException.

Kotlin

try {
    // some suspend function call
} catch (e: [1]) {
    println("Cancelled")
}

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

ACancellationException

BTimeoutException

CIllegalArgumentException

DIOException

Attempts:

3 left

💡 Hint

Common Mistakes

Catching a generic Exception instead of CancellationException

Using unrelated exception types like IOException

The CancellationException is the specific exception thrown when a coroutine is cancelled.

2fill in blank

medium

Complete the code to rethrow a CancellationException inside a catch block.

Kotlin

try {
    // some suspend function
} catch (e: Exception) {
    if (e is [1]) throw e
    println("Other exception")
}

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AIOException

BCancellationException

CNullPointerException

DIllegalStateException

Attempts:

3 left

💡 Hint

Common Mistakes

Not rethrowing CancellationException causes coroutine to continue unexpectedly

Rethrowing unrelated exceptions

When catching exceptions, CancellationException should be rethrown to properly cancel the coroutine.

3fill in blank

hard

Fix the error in the code to properly handle coroutine cancellation.

Kotlin

try {
    delay(1000)
} catch (e: [1]) {
    println("Cancelled")
}

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AException

BRuntimeException

CCancellationException

DError

Attempts:

3 left

💡 Hint

Common Mistakes

Catching generic Exception hides cancellation

Catching Error or RuntimeException is incorrect

The delay function throws CancellationException when the coroutine is cancelled, so it must be caught specifically.

4fill in blank

hard

Fill both blanks to create a map of words to their lengths only if length is greater than 3.

Kotlin

val words = listOf("apple", "bat", "carrot", "dog")
val lengths = words.filter { word -> [2] > 3 }.associate { word -> word to [1] }

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Aword.length

Blen(word)

Cword.length()

Dword.size

Attempts:

3 left

💡 Hint

Common Mistakes

Using Python's len() function

Using method call syntax like length() which is invalid in Kotlin

In Kotlin, word.length gives the length of the string. The condition checks if length is greater than 3.

5fill in blank

hard

Fill all three blanks to create a map of uppercase words to their lengths if length is greater than 3.

Kotlin

val words = listOf("apple", "bat", "carrot", "dog")
val result = words.filter { word -> [3] > 3 }.associate { word -> [1] to [2] }

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Aword.uppercase()

Bword.length

Dword.toUpperCase()

Attempts:

3 left

💡 Hint

Common Mistakes

Using deprecated toUpperCase() instead of uppercase()

Using Python style functions like len()

word.uppercase() converts the word to uppercase in Kotlin. word.length gives the length. The condition checks if length is greater than 3.