Jobs

The result of running an asynchronous task is referred to as a job. Just as the Thread object represents an actual OS thread, the Job object represents an actual coroutine.

For instance, consider the following function that initiates a coroutine to generate a universally unique identifier (UUID) asynchronously and returns it:

fun fastUuidAsync() = GlobalScope.async { 
    UUID.randomUUID() 
}

However, if we execute this code from our main method, it won’t print the expected UUID value. Instead, it will produce a result similar to the following:

> DeferredCoroutine{Active} 

The object returned from a coroutine is known as a job. Now, let’s explore what a job is and how to use it correctly.

To illustrate this concept, consider the following code snippet:

fun main() {
    runBlocking {
        val job: Deferred<UUID> = fastUuidAsync()
        println(job.await())
    }
}

A job has a simple life cycle and can be in one of...