A job in the state new can be started in many ways, but commonly it will be done by calling start() or join(), the difference being that the former will start the job without waiting for it to complete, whereas the latter will suspend execution until the job completes. Take this example into consideration:

fun main(args: Array<String>) {
    val job = launch(start = CoroutineStart.LAZY) {
        delay(3000)
    }

    job.start()
}

The mentioned code will not suspend execution when job.start() is invoked, so the application will complete its execution without waiting for job to complete.

If we use join(),we will force the application to wait for job to complete, as demonstrated:

fun main(args: Array<String>) = runBlocking {
    val job = launch(start = CoroutineStart.LAZY) {
        delay(3000)
    }

    job.join()
}

Any job that has been started is therefore active, and it will be active until it completes execution or until cancellation is requested.