title: jsessionid is saved and used even after reboot\re-installation of the service
body: <p>I have a Tomcat 7 web server.
  After login to it I can see under Cookies that there is jsessionid which, from what I have read is saving the id of the session instance between the user and the web server.</p>
  
  <p>But the thing I cannot understand is that after I login and I stay in the browser.
  I can stop the server, even un install it from the system and re-install it. 
  and then after I restart it I can continue navigating in the website without needing to enter credentials or anything like that, as if nothing happened in the background - I just can move on with the same jesssionId.</p>
  
  <p>So basically I will divide my question into sub-question so it will be easier to answer:
  1. How is it even possible that after stopping the service  or even un install it it can still happen?
  2. How excatly is the jesessionID created? I mean is it possible that it is <strong>the same jsession</strong> id? 
  3.When exactly does the jsessionID is being created?
  4. Is it possible to change this behavior and "invalidate" the session so the user will have to re-enter his credentials?
  5. Following question #4, what is common in most of the services? demand to login again or to enable the use of the old session id ?</p>
  
  <p>Thanks a lot!</p>