title: Login page and Servlet process flow
body: <p>I am trying to understand a process involved in logging in a user. I was told a servlet needed to be made in order to access the headers of a request/response. </p>
  
  <p>So one was made, it grabs the header info, then checks to make sure the user is a valid user in the database. If so, it sets the session with this user. If not, it directs to the registration page.</p>
  
  <p>My issues is in understanding what calls this servlet, is a "start page needed to call this servlet?"</p>