Hibernate is setup as the JPA provider. Another JPA provider,
like EclipseLink, could be specified and if all your code just uses
JPA nothing else would need to be changed.
The Person & Address classes are explicitly configured, and
JPA's scanning for entity beans is turned off by specifying the exclude-unlisted-classes element.
Some Hibernate specific configuration items are set within the properties element.
Excerpt from META-INF/persistence.xml
<?xml version="1.0" encoding="UTF-8"?>
<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_1_0.xsd"
version="1.0">
...
<persistence-unit name="simple-jpa">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<class>org.springbyexample.orm.jpa.bean.Person</class>
<class>org.springbyexample.orm.jpa.bean.Address</class>
<exclude-unlisted-classes/>
<properties>
<property name="hibernate.dialect" value="org.hibernate.dialect.HSQLDialect" />
<property name="hibernate.show_sql" value="true" />
<property name="hibernate.cache.provider_class" value="org.hibernate.cache.HashtableCacheProvider" />
</properties>
</persistence-unit>
...
</persistence>