What are coroutines,How are they make asynchronous operation easy in Kotlin ?

Coroutine are light-weight threads. A light weight thread means it doesn’t map on native thread, so it doesn’t require context switching on processor, so they are faster. Coroutines is a new way of writing asynchronous, non-blocking code in kotlin.

How to implement corountine ?

These are the functions to start the coroutine:

1. launch{}

2. async{}

Launch vs Async in Kotlin Coroutines

The difference is that the launch{} does not return anything and the async{} returns an instance of Deferred<T>, which has an await function that returns the result of the coroutine like we have future in Java. and we do future.get() in Java to the get the result.

fun main(args: Array<String>) {
    launch { // launch new coroutine in background and continue
        delay(1000L) // non-blocking delay for 1 second (default time unit is ms)
        println("World!") // print after delay
    }
    println("Hello,") // main thread continues while coroutine is delayed
    Thread.sleep(2000L) // block main thread for 2 seconds to keep JVM alive
}

fun main(args: Array<String>) {

launch { // launch new coroutine in background and continue

delay(1000L) // non-blocking delay for 1 second (default time unit is ms)

println("World!") // print after delay

}

println("Hello,") // main thread continues while coroutine is delayed

Thread.sleep(2000L) // block main thread for 2 seconds to keep JVM alive

}

Let see the use of async?

// Parallel execution
private fun taskA() {
  val one = async(CommonPool) {
      taskB()
  }
  val two = async(CommonPool) {
      taskC()
  }
  launch(CommonPool) {
      val combined = one.await() + "-->" + two.await()
      println("Combined : " + combined)
  }
}
// The output is
// Combined : taskB-->taskC

// Parallel execution

private fun taskA() {

val one = async(CommonPool) {

taskB()

}

val two = async(CommonPool) {

taskC()

}

launch(CommonPool) {

val combined = one.await() + "-->" + two.await()

println("Combined : " + combined)

}

// The output is

// Combined : taskB-->taskC

manish choudhary 16 April 2018

. . .

What are coroutines,How are they make asynchronous operation easy in Kotlin ?

How to implement corountine ?

Launch vs Async in Kotlin Coroutines

Let see the use of async?

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