Kotlin Kotlin Coroutines 3

Question 1

What is the difference between `StateFlow` and `SharedFlow` in Kotlin?

Accepted Answer

StateFlow holds the latest value and replays it to new collectors; SharedFlow is configurable

Answer

`StateFlow` always holds and replays the latest value to new subscribers, while `SharedFlow` is configurable with custom replay and buffering.

Question 2

What does `SupervisorJob` do differently from a regular `Job`?

Accepted Answer

It prevents child coroutine failures from cancelling sibling coroutines

Answer

With `SupervisorJob`, a failure in one child coroutine does not cancel its siblings, unlike a regular `Job` where failure propagates.

Question 3

Which operator transforms each emitted value of a Flow into another Flow and flattens the results?

Accepted Answer

flatMapLatest

Answer

`flatMapLatest` transforms each value into a new Flow, cancelling the previous inner Flow when a new value arrives.

Question 4

What is the purpose of `CoroutineExceptionHandler`?

Accepted Answer

To handle uncaught exceptions in coroutines as a last resort

Answer

`CoroutineExceptionHandler` is a context element that catches uncaught exceptions from coroutines that would otherwise crash the application.

Question 5

What does `produce` coroutine builder create?

Accepted Answer

A Channel that receives values produced by a coroutine

Answer

`produce` creates a `ReceiveChannel` and launches a coroutine that produces values into it, useful for producer-consumer patterns.

Kotlin Practice Test