Exception handling in coroutines in Kotlin - Mini Project: Build & Apply

Exception handling in coroutines

📖 Scenario: You are building a simple Kotlin program that uses coroutines to perform tasks asynchronously. Sometimes, these tasks might fail with errors. You want to learn how to catch and handle these errors properly inside coroutines.

🎯 Goal: Learn how to write Kotlin coroutines that handle exceptions using try-catch blocks and coroutine builders.

📋 What You'll Learn

Create a coroutine that throws an exception

Add a variable to hold the error message

Use try-catch inside a coroutine to catch the exception

Print the caught error message

💡 Why This Matters

🌍 Real World

Handling errors in asynchronous tasks is important to keep apps stable and responsive.

💼 Career

Many Kotlin developers use coroutines for background work and must handle exceptions properly to avoid crashes.

1

Create a coroutine that throws an exception

Write a suspend function called riskyTask that throws an IllegalArgumentException with the message "Something went wrong".

Kotlin

# Write the suspend function riskyTask that throws IllegalArgumentException
# Your code here

Need a hint?

Use throw IllegalArgumentException("Something went wrong") inside the suspend function.

2

Add a variable to hold the error message

Create a mutable variable called errorMessage of type String? and set it to null.

Kotlin

suspend fun riskyTask() {
    throw IllegalArgumentException("Something went wrong")
}

// Create a variable errorMessage of type String? and set it to null
# Your code here

Need a hint?

Use var errorMessage: String? = null to create the variable.

3

Use try-catch inside a coroutine to catch the exception

Write a runBlocking block. Inside it, call riskyTask() inside a try block. Catch IllegalArgumentException and set errorMessage to the exception's message.

Kotlin

suspend fun riskyTask() {
    throw IllegalArgumentException("Something went wrong")
}

var errorMessage: String? = null

// Use runBlocking and try-catch to call riskyTask and catch the exception
# Your code here

Need a hint?

Use runBlocking { try { riskyTask() } catch (e: IllegalArgumentException) { errorMessage = e.message } }.

4

Print the caught error message

Add a println statement after the runBlocking block to print the value of errorMessage.

Kotlin

import kotlinx.coroutines.runBlocking

suspend fun riskyTask() {
    throw IllegalArgumentException("Something went wrong")
}

var errorMessage: String? = null

fun main() = runBlocking {
    try {
        riskyTask()
    } catch (e: IllegalArgumentException) {
        errorMessage = e.message
    }
}

// Print the errorMessage here
# Your code here

Need a hint?

Use println(errorMessage) after the coroutine block to show the error message.