diagram-unhappy.sequence

User->Application: GET /greeting/2
Application->GreetingController: greeting(2)
GreetingController->GreetingService: greeting(2)
GreetingService->GreetingRepository: findById(2)
GreetingRepository-->GreetingService: Optional.empty
GreetingService-->GreetingController: NoSuchElementException
GreetingController-->Application: NoSuchElementException
Application-->User: 200