CoroutineExceptionHandler in Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a CoroutineExceptionHandler that prints the exception message.

Kotlin

val handler = CoroutineExceptionHandler { _, exception ->
    println("Caught: " + [1].message)
}

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Ait

Bexception

Cerror

Dthrowable

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong parameter name like 'it' or 'error' which are not defined here.

The exception parameter holds the caught exception, so accessing exception.message prints its message.

2fill in blank

medium

Complete the code to launch a coroutine with the exception handler attached.

Kotlin

GlobalScope.launch([1]) {
    throw RuntimeException("Error!")
}

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Ahandler

BDispatchers.IO

CDispatchers.Main

DSupervisorJob()

Attempts:

3 left

💡 Hint

Common Mistakes

Passing a dispatcher instead of the exception handler.

The handler is the CoroutineExceptionHandler instance that handles exceptions in the coroutine.

3fill in blank

hard

Fix the error in the CoroutineExceptionHandler usage to properly catch exceptions.

Kotlin

val handler = CoroutineExceptionHandler { _, [1] ->
    println("Caught: " + exception.message)
}

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Aexception

Berror

Cthrowable

De

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different parameter name but referencing 'exception' inside the block.

The lambda parameter must be named exception to match the usage inside the block.

4fill in blank

hard

Fill both blanks to create a CoroutineScope with a SupervisorJob and the exception handler.

Kotlin

val scope = CoroutineScope([1] + [2])

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ASupervisorJob()

Bhandler

CDispatchers.Default

DJob()

Attempts:

3 left

💡 Hint

Common Mistakes

Using Job() instead of SupervisorJob().

Not including the exception handler.

Combining SupervisorJob() and handler creates a scope that supervises child coroutines and handles exceptions.

5fill in blank

hard

Fill all three blanks to define a CoroutineExceptionHandler that logs the error, then launch a coroutine with it and a dispatcher.

Kotlin

val handler = CoroutineExceptionHandler { _, [1] ->
    println("Error: " + [2].message)
}

GlobalScope.launch([3] + handler) {
    throw IllegalStateException("Oops")
}

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

Aexception

CDispatchers.Default

DDispatchers.IO

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for the exception parameter and inside the block.

Omitting the dispatcher or using the wrong one.

The exception parameter is named exception in the handler, used to print the message. The coroutine is launched with Dispatchers.Default plus the handler.