title: Android, what really happens after force closing an application?
body: <p>I have an stock market application. When user login to application, server sends me a session key. This session is valid until user logout the application or don't do anything for several minutes. </p>
  
  <p>My first problem (that is solved already) was when after login to application, user click home button and after that click on icon of application. Now, after login, a message (sent by server) showed "your user id is in use". I have solved this issue by saving session id in shared preferences.</p>
  
  <p>Now, the client reported that we have same issue based of this story.</p>
  
  <ul>
  <li>User login to application</li>
  <li>After that user clicks home button</li>
  <li>User goes to settings/applications/manage applications</li>
  <li>Selects application and then in "Application Info" page, clicks on Force Stop button</li>
  <li>User comes back to application list again and selects the application</li>
  <li>After login, "Session Expired" message will show and application directed to login page again</li>
  <li>Now, when user try to login, the above message ("your user id is in use") will show while session id is not expired.</li>
  </ul>
  
  <p>I want to know, what "Force Close" button really do? Does it clean all instances of activities? When I click and hold Home button, I can see that I still have an instance of the application in memory. Therefore, what is the role of "Force Close" button?</p>
  
  <ul>
  <li>Now, if user enter his/her password "your user id is in use" will show again.</li>
  </ul>