Let's break down our persistence unit (pu).
This line defines the pu name and the transaction type used:
<persistence-unit name="ch02-jpa-pu" transaction-type="JTA">
The following line shows the provider the JPA implementation used:
<provider>org.hibernate.ejb.HibernatePersistence</provider>
It is the datasource name that will be accessed through JNDI:
<jta-data-source>userDb</jta-data-source>
This line lets all your entities be available for this pu, so you don't need to declare each one:
<exclude-unlisted-classes>false</exclude-unlisted-classes>
This block allows the database objects to be created if they don't exist:
<properties> <property name="javax.persistence.schema- generation.database.action" value="create"/> </properties> ...
