title: How to use JDO persistence manager?
body: <p>I have two questions regarding how to create / use the JDO persistence manager (PM, hereafter). </p>
  
  <p>Say, in a Java web application, if I have 10 entities, which can be logically grouped into 2 groups (for example, 5 user related entities and 5 business related entities)</p>
  
  <ol>
  <li>Should I need two different PMs to manage these 2 groups or only one PM is enough?</li>
  <li>Regarding the initialization, shall I use singleton instance of a PM (which will be shared by all the user's using the app at a given point of time) or should I create a PM for each and every session?</li>
  </ol>