Exception handling in coroutines in Android Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of exception handling in Kotlin coroutines?

Exception handling in Kotlin coroutines helps manage errors that occur during asynchronous tasks, preventing app crashes and allowing graceful recovery.

beginner

Which coroutine builder automatically propagates exceptions to its parent coroutine?

The launch builder propagates exceptions to its parent coroutine, which can then handle or cancel the child coroutine.

beginner

How does try-catch work inside a coroutine?

You can use try-catch blocks inside a coroutine to catch exceptions thrown by suspend functions or other code, just like in regular synchronous code.

intermediate

What is the role of CoroutineExceptionHandler?

CoroutineExceptionHandler is a special context element that catches uncaught exceptions in coroutines launched with launch, allowing centralized error handling.

intermediate

Why should exceptions in async coroutines be handled differently?

Exceptions in async coroutines are deferred until await() is called, so you must handle exceptions when awaiting the result, not when launching.

Which coroutine builder requires you to handle exceptions when calling await()?

A async

B launch

C runBlocking

D withContext

async defers exceptions until await() is called, so you handle exceptions there.

What happens if an exception is not caught inside a launch coroutine?

A It is propagated to the parent coroutine

B It crashes the app immediately

C It is ignored silently

D It is logged but does not affect the app

Exceptions in launch coroutines propagate to their parent, which can handle or cancel them.

Which of these is a correct way to catch exceptions inside a coroutine?

A Using <code>catch</code> method on the coroutine builder

B Using <code>try-catch</code> inside the coroutine block

C Using <code>finally</code> outside the coroutine

D Exceptions cannot be caught in coroutines

You can use try-catch blocks inside coroutines to catch exceptions.

What is the purpose of CoroutineExceptionHandler?

A To cancel coroutines automatically

B To delay coroutine execution

C To handle uncaught exceptions in <code>launch</code> coroutines

D To convert exceptions to logs only

CoroutineExceptionHandler catches uncaught exceptions in launch coroutines.

Where should you handle exceptions when using async?

A When launching the coroutine

B Before starting the coroutine

C Exceptions are handled automatically

D When calling <code>await()</code>

Exceptions in async coroutines are thrown when await() is called.

Explain how exception handling differs between launch and async coroutines in Kotlin.

Think about when exceptions are thrown and caught in each builder.

Describe how to use CoroutineExceptionHandler to handle errors in a coroutine.

It is a context element that catches uncaught exceptions.