Exception handling in coroutines in Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to catch exceptions inside a coroutine.

Kotlin

launch {
    try {
        // Some suspending function
        fetchData()
    } catch ([1]: Exception) {
        println("Error caught")
    }
}

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

Ae

Berror

Cex

Dexception

Attempts:

3 left

💡 Hint

Common Mistakes

Using a keyword or invalid variable name in catch block.

Not providing a variable name after catch.

The variable e is commonly used to catch exceptions in Kotlin. It holds the caught exception object.

2fill in blank

medium

Complete the code to handle exceptions globally in a CoroutineScope.

Kotlin

val handler = CoroutineExceptionHandler { _, [1] ->
    println("Caught $[1]")
}

CoroutineScope(Dispatchers.Default + handler).launch {
    throw RuntimeException("Fail")
}

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Athrowable

Berror

Ce

Dexception

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect parameter names that don't match the handler signature.

Confusing the exception variable with the context.

The CoroutineExceptionHandler receives a Throwable as the second parameter, commonly named throwable.

3fill in blank

hard

Fix the error in the coroutine exception handling code.

Kotlin

val handler = CoroutineExceptionHandler { _, throwable ->
    println("Caught: $[1]")
}

GlobalScope.launch(handler) {
    throw Exception("Oops")
}

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Aerror

Bthrowable

Ce

Dex

Attempts:

3 left

💡 Hint

Common Mistakes

Referencing a variable name not declared in the lambda parameters.

Using a different variable name inside the lambda body.

The variable throwable is the correct name used in the lambda parameter and must be referenced inside the lambda.

4fill in blank

hard

Fill both blanks to create a map of word lengths filtering words longer than 3 characters.

Kotlin

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

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Alength

B>

C<

Dcount

Attempts:

3 left

💡 Hint

Common Mistakes

Using count without parentheses which is a function.

Using wrong comparison operators like < instead of >.

length gets the length of the string, and > filters words longer than 3 characters.

5fill in blank

hard

Fill all three blanks to create a map of uppercase keys and values filtered by positive values.

Kotlin

val data = mapOf("a" to 1, "b" to -2, "c" to 3)
val result = data.mapKeys { it.key.[1]() }
    .filter { it.value [2] 0 }
    .mapValues { it.[3] }

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AtoUpperCase

B>

Cvalue

DtoLowerCase

Attempts:

3 left

💡 Hint

Common Mistakes

Using toLowerCase() instead of uppercase.

Filtering with wrong comparison operator.

Using key instead of value in mapValues.

toUpperCase() converts keys to uppercase, > filters positive values, and value returns the map's value.