title: Handling exceptions but where ? Service Layer or Controller?
body: <p>I was wondering where exactly do you handling exception ? it is in the service layer or the controller ?</p>
  
  <p>If an error happen in the service layer.. and that this error must somehow be showed to the user.. how do we proceed ?</p>
  
  <p>EDIT</p>
  
  <p>I will explain, bring in context an account where the user have to specify username and password.. if that go through the AuthentificationService and that the username and password doesnt match i have to tell the user.. how i handle this scenario ? is the service layer will throw an exception ?</p>
  
  <p>Thanks.</p>