title: why my JPA annotated classes are not discovered implicitly?
body: <p>My <code>persistence.xml</code> looks like:</p>
  
  <pre><code>&lt;persistence&gt;
    &lt;persistence-unit name="test"&gt;
      &lt;provider&gt;org.hibernate.ejb.HibernatePersistence&lt;/provider&gt;
      &lt;class&gt;com.XXX.Abc&lt;/class&gt;
      &lt;properties&gt;
        &lt;property name="hibernate.archive.autodetection" value="true" /&gt;
        ..
      &lt;/properties&gt;
    &lt;/persistence-unit&gt;
  &lt;persistence&gt;
  </code></pre>
  
  <p>Everything works fine. When I'm removing <code>&lt;class&gt;</code> directive I'm getting an exception from <code>EntityManager.find(Abc.class, 1)</code>:</p>
  
  <pre><code>java.lang.IllegalArgumentException: Unknown entity: com.XXX.Abc
  </code></pre>
  
  <p>Looks like hibernate can't discover my annotated classes although I'm using <code>@Entity</code>.. Why?</p>