title: No Persistence Provider for EntityManager named foo
body: <p>Yes I've already searched here for this question but I have this problem after the researches.</p>
  
  <p>So, I'm making a simple standalone project, containing only Entities and DAOs.
  I'm using IntelliJ.</p>
  
  <p>EDIT: My DB connection informations are good, I'm sure. And I've got another project (GWT) and I'm using the same method -> it works</p>
  
  <p>My META-INF folder is in the root src folder, so this is my persistence.xml:</p>
  
  <pre><code>`&lt;persistence-unit name="jpa"&gt;
      &lt;!--&lt;provider&gt;org.eclipse.persistence.jpa.PersistenceProvider&lt;/provider&gt;--&gt;
      &lt;class&gt;ejbpersistance.entities.User&lt;/class&gt;
      &lt;class&gt;ejbpersistance.entities.Comment&lt;/class&gt;
      &lt;class&gt;ejbpersistance.entities.Article&lt;/class&gt;
      &lt;properties&gt;
          &lt;property  name="javax.persistence.jdbc.url"  value="jdbc:mysql://localhost:3306/ejb"/&gt;
          &lt;property  name="javax.persistence.jdbc.user"  value="root"/&gt;
          &lt;property  name="javax.persistence.jdbc.password"  value="root"/&gt;
          &lt;property  name="javax.persistence.jdbc.driver"  value="com.mysql.jdbc.Driver"/&gt;
      &lt;/properties&gt;
  &lt;/persistence-unit&gt;`
  </code></pre>
  
  <p>and this is my code:</p>
  
  <pre><code>public EntityManagerFactory getEntityManagerFactory() {
      if(emf == null)
          emf = Persistence.createEntityManagerFactory("jpa");
      return emf;
  }
  </code></pre>
  
  <p>I tried with Hibernate provider, Eclipse provider but always this problem.
  Can someone help me ? And if I missed something in another topic concerning this issue, I apologize for the time loss.</p>