Where as in this case, the last line "Hello " executes first

# coroutines

[chansek]

Where as in this case, the last line "Hello " executes first

[octylFractal]

launch is async, so while in the first case the delay(500L) inside coroutineScope prevented the last line from executing until after launch had finished, it doesn't do that in this case

[chansek]

In the first case also, delay(500L) is inside launch which is async. So why it prevents the last line to be executed?

[octylFractal]

coroutineScope suspends until all inside coroutines are complete, including `launch`es

[octylFractal]

ref coroutineScope docs:

This function returns as soon as given block and all its children coroutines are completed.

[chansek]

Does that mean suspending and blocking is same?

[chansek]

Because, blocking context also prevent the last line to be executed

[octylFractal]

no, they are different -- suspending won't take up a thread, blocking will

[octylFractal]

if you add some more prints, you can notice that the launch in the coroutineScope will actually run async to the delay(100L), despite runBlocking only having one thread

[octylFractal]

if delay blocked, it wouldn't run until after the println("... from coroutine scope")

[chansek]

Looks like, I am understanding a bit now. Thanks a lot for the help.

I will explore a bit more. Hope you wouldn't mind if I have further basic doubts like this

[halim]

launch is coroutine build of type Job so its return immedatly (like future of comptetebalefuture) so the main is pass the second instruction (println("hello")) and not wait for launch to complete, also launch is delay fo 1 sec and this is an other reason the print ("hello") on first, delay is function that execute is separate thread (with executor named "scheduler") so the main-thread will be free to continue execution (not println("world")) because launch in this case is suspended (blocking) until delay finish) so main-thread pass to rest of your code (println("hello")), when delay finish its resume in main-thread (context of resume by default is the context of caller and in this case is main-thread you can change it if you implement continuation interface) and println("world")