Try this
<?xml version="1.0" ?>
<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">
<persistence-unit name="myapp">
<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
</persistence-unit>
</persistence>