title: Issue with persistence.xml file when trying to do maven clean install
body: <p>I am getting an error when I try to do a clean/compile/install for one of my modules. </p>
  
  <pre><code>[ERROR] Failed to execute goal org.codehaus.mojo:hibernate3-maven-plugin:3.0:run 
  (generate-drop-ddl) on project baseImpl: There was an error creating the AntRun task. 
  An Ant BuildException has occured: Problems in creating a configuration for JPA. 
  Have you remembered to add hibernate EntityManager jars to the classpath ?: 
  InvocationTargetException: Invalid persistence.xml.
  [ERROR] Error parsing XML (line-1 :  column -1): cvc-complex-type.2.4.d: 
  Invalid content was found starting with element 'class'. 
  No child element is expected at this point.
  </code></pre>
  
  <p>I have another module that compiles/installs fine, and the only difference is that it references different classes, so I can't figure out what's wrong with my persistence.xml, or if that is even the problem.</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;persistence xmlns="http://java.sun.com/xml/ns/persistence"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd" version="2.0"&gt;
  &lt;persistence-unit name="appPersistenceUnit"&gt;
      &lt;provider&gt;org.hibernate.ejb.HibernatePersistence&lt;/provider&gt;
      &lt;class&gt;base.bo.Address&lt;/class&gt;
      &lt;class&gt;base.bo.Club&lt;/class&gt;
      &lt;class&gt;base.bo.Team&lt;/class&gt;
      &lt;exclude-unlisted-classes&gt;true&lt;/exclude-unlisted-classes&gt;   
  &lt;/persistence-unit&gt;
  &lt;/persistence&gt;
  </code></pre>