Hi all! What is the difference between Job and SupervisorJob in case of Exception Handling?

class Presenter() : CoroutineScope {
        private val job = Job()

        override val coroutineContext: CoroutineContext
            get() = job + Dispatchers.Main

        override fun onDestroy() {
            job.cancel()
        }

        fun loadData() {
            launch {
                try {
                    //loadData().async()
                } catch (e: Exception) {
                    //handle exception
                }
            }

        }
    }

class Presenter() : CoroutineScope {
        private val job = SupervisorJob()

        override val coroutineContext: CoroutineContext
            get() = job + Dispatchers.Main

        override fun onDestroy() {
            job.cancel()
        }

        fun loadData() {
            launch {
                try {
                    //loadData().async()
                } catch (e: Exception) {
                    //handle exception
                }
            }

        }
    }

Did you read docs of SupervisorJob?

Yes, looks like second example is the way to go in most cases.

What is the actual difference between SupervisorJob() and CoroutineScope constructor?

This question doesn’t make make sense, Job and Scope are different things

@gildor The only part that is still unclear for me is why the following solution should work? use the following shortcut via

CoroutineScope

constructor:

class UserViewModel: ViewModel, CoroutineScope by CoroutineScope(Dispatchers.Default) {
    override fun onCleared() {
        super.onCleared()
        cancel()
    }
}

The working solution is to create new Job(), after exception is caught:

CoroutineExceptionHandler { _, throwable ->
        //onError(throwable)
        job = Job()
    }

job = Job() - this looks wrong

The question is related to Roman Elizarov answer: https://github.com/Kotlin/kotlinx.coroutines/issues/996#issuecomment-468890079 SupervisorJob() works great but the second solution does not.

But this not related to CoroutineExceptionHandler

ok - now i got it 🙂

or use the following shortcut via CoroutineScope constructor:

I actually not sure what Romain means by this, this is exactly the same as version above, just more concise

Yeap, SupervisorJob works great!