title: Multiple persistence-unit tags in one persistence.xml
body: <p>I'm working now with a JPA 2.0 project (in Eclipse Indigo). In my persistence.xml file I need to specify two &lt;persistence-unit> tags, because I have two different database to work with. Doing this, I get the following warning:</p>
  
  <blockquote>
    <p>Multiple persistence units defined - only the first persistence unit will be recognized</p>
  </blockquote>
  
  <p>Even more, if I create my entities and put it in my second &lt;persistence-unit>, I get an error saying that my entity isn't declared in a persistence-unit:</p>
  
  <blockquote>
    <p>Class "my.package.MyClass" is mapped, but is not included in any persistence unit</p>
  </blockquote>
  
  <p>So, the question is: is possible to declare (and use them as expected) many &lt;persistence-unit> tags in persistence.xml file? If yes, what do I need to do for getting the accurate behavior?</p>
  
  <p>Thanks!</p>