How to Start Coroutines In Kotlin?

9 minutes read

In Kotlin, coroutines are started using the launch function from the coroutineScope builder. This function takes a lambda expression as a parameter, which contains the code to be executed concurrently. Inside this lambda expression, you can perform asynchronous tasks without blocking the main thread. Additionally, you can use async to start a coroutine that returns a result, which can be later retrieved using await. By using coroutines, you can achieve better performance and readability in your Kotlin code.

Best Kotlin Books to Read in July 2024

1
Atomic Kotlin

Rating is 5 out of 5

Atomic Kotlin

2
Kotlin Cookbook: A Problem-Focused Approach

Rating is 4.9 out of 5

Kotlin Cookbook: A Problem-Focused Approach

3
Head First Kotlin: A Brain-Friendly Guide

Rating is 4.8 out of 5

Head First Kotlin: A Brain-Friendly Guide

4
Kotlin in Action

Rating is 4.7 out of 5

Kotlin in Action

5
Kotlin In-Depth: A Guide to a Multipurpose Programming Language for Server-Side, Front-End, Android, and Multiplatform Mobile (English Edition)

Rating is 4.6 out of 5

Kotlin In-Depth: A Guide to a Multipurpose Programming Language for Server-Side, Front-End, Android, and Multiplatform Mobile (English Edition)

6
Kotlin Design Patterns and Best Practices: Build scalable applications using traditional, reactive, and concurrent design patterns in Kotlin, 2nd Edition

Rating is 4.5 out of 5

Kotlin Design Patterns and Best Practices: Build scalable applications using traditional, reactive, and concurrent design patterns in Kotlin, 2nd Edition

7
Kotlin Programming: The Big Nerd Ranch Guide (Big Nerd Ranch Guides)

Rating is 4.4 out of 5

Kotlin Programming: The Big Nerd Ranch Guide (Big Nerd Ranch Guides)

8
Java to Kotlin

Rating is 4.2 out of 5

Java to Kotlin

9
Kotlin Essentials (Kotlin for Developers)

Rating is 4.1 out of 5

Kotlin Essentials (Kotlin for Developers)


What is coroutine context propagation in Kotlin?

Coroutine context propagation in Kotlin refers to the way coroutine contexts are automatically propagated when a coroutine is launched in a different context. This means that when a coroutine is launched in a specific context (such as Dispatchers.Main), the coroutine will maintain that context throughout its execution, even if it is suspended and later resumed in a different context.


This feature allows developers to easily switch between different execution contexts without having to manually pass the context around. Coroutine context propagation makes it easier to write asynchronous code in Kotlin by ensuring that coroutines retain the correct execution context throughout their lifecycle.


What is a coroutine job in Kotlin?

In Kotlin, a coroutine job is a handle to a coroutine that allows for control and manipulation of its lifecycle. By using a coroutine job, you can start, cancel, pause, and resume a coroutine, as well as query its current state and wait for its completion. This gives you more control and flexibility when working with coroutines in Kotlin.


How to handle thread safety in Kotlin coroutines?

In Kotlin coroutines, thread safety can be ensured by following these guidelines:

  1. Use the synchronized keyword to ensure that only one coroutine is accessing a shared resource at a time.
  2. Use thread-safe data structures such as ConcurrentHashMap or AtomicInteger to ensure that multiple coroutines can safely access and modify shared data.
  3. Use Mutex or Semaphore to provide a mutual exclusion mechanism for critical sections of code that should not be accessed by multiple coroutines simultaneously.
  4. Use runBlocking or coroutineScope to ensure that a coroutine is executed in a thread-safe manner within its scope.
  5. Avoid using mutable shared state whenever possible, and prefer immutable data structures or local variables instead.
  6. Use volatile keyword for volatile fields in classes which can be accessed by multiple coroutines.


By following these guidelines, you can ensure that Kotlin coroutines are executed in a thread-safe manner, minimizing the risk of data corruption or race conditions.


What is the difference between launch and async functions in Kotlin coroutines?

  1. Invocation:
  • Launch functions (launch, GlobalScope.launch) are used to start a new coroutine and run the specified block of code concurrently with the parent coroutine. It does not return any result.
  • Async functions (async, GlobalScope.async) are used to start a new coroutine and run the specified block of code concurrently with the parent coroutine, but it returns a Deferred object that can be used to retrieve the result of the computation.
  1. Return type:
  • Launch functions return a Job object that can be used to control and monitor the coroutine.
  • Async functions return a Deferred object that can be used to retrieve the result of the computation.
  1. Error handling:
  • Launch functions do not provide a way to propagate exceptions from the coroutine to the calling code.
  • Async functions allow the calling code to retrieve the result of the computation and handle any exceptions that occurred during its execution.
  1. Use case:
  • Launch functions are typically used when you want to perform some task in the background without worrying about the result or when you want to execute some code concurrently.
  • Async functions are used when you want to perform some task in the background and retrieve the result of the computation once it is completed.


Overall, async functions are more versatile as they allow you to retrieve the result of the computation and handle any exceptions, whereas launch functions are more lightweight and are mainly used for fire-and-forget tasks.

Facebook Twitter LinkedIn Telegram Whatsapp Pocket

Related Posts:

Coroutines are a powerful feature in the Kotlin programming language that allows for asynchronous programming. They provide a way to write asynchronous code that looks much like synchronous code and is easier to read and maintain. Here is an overview of how to...
To test coroutines that use the await() function in Kotlin, you can use the runBlocking function provided by the kotlinx.coroutines.test package. This function allows you to write tests for suspending functions that use coroutines.Within your test function, yo...
To call a Kotlin function from JavaScript, you can use the Kotlin/JS plugin that allows you to compile Kotlin code to JavaScript. First, define your Kotlin function in a Kotlin file using the external keyword to tell the Kotlin compiler that this function will...
In Kotlin, you can wait for an async operation to complete using coroutines. You can use the runBlocking function, which blocks the current thread until the coroutine inside it completes. Another option is to use the await function, which waits for the result ...
Merging flow and channel in Kotlin allows you to combine the benefits of both concepts for more versatile and powerful asynchronous programming.Kotlin flow is a declarative way of working with asynchronous data streams, providing built-in operators like map, f...
To run blocking Java code concurrently in Kotlin, you can use the runBlocking function from Kotlin's coroutine library. This function allows you to execute blocking code within a coroutine without blocking the main thread. You can use this function to wrap...