title: Identify only GAE users
body: <p>I am quite new to openID and GAE and there are lots of documentation that I get confused. So</p>
  
  <ol>
  <li>I am building a Java web application.</li>
  <li>I have GAE for Business.</li>
  </ol>
  
  <p>As I understand GAE are automatically become openID providers. Can I in my Java web app identify only my GAE users using openID, like when user clicks login button it redirects to my GAE login page and identifies them? If user is not my GAE user my Java app rejects the access.</p>
  
  <p>If something is not clear just tell me, because English is not my native language.</p>