Is it possible to have Handler with Applcation scope , in session scope services

[Apostolopoulos Paris]

Hi!

I want to make some login validation, before the client uses a session
scope service! Due to simplicity, I would like to know if the handler
that is going to check the username and password , can be defined as
application scope and the same instance hanlder to serve all the
sessions! Is that possible? What is going on when multiple session
request end up in the server? The developer has to make tha instace as
thread -safe?