Bootstrapping Hibernate as a JPA provider can be done in a JPA-spec compliant manner or using a proprietary bootstrapping approach. The standardized approach has some limitations in certain environments. But aside from those limitations, it is highly recommended that you use JPA-standardized bootstrapping.
| Under the covers, all of Hibernate’s JPA bootstrapping makes use of its core bootstrapping. Be sure to see the Native Bootstrapping guide as well. |
JPA-compliant bootstrapping
In JPA we are ultimately interested in bootstrapping an javax.persistence.EntityManagerFactory instance. The
JPA specification defines 2 primary standardized bootstrap approaches depending on how the application intends to
access the javax.persistence.EntityManager instances from an EntityManagerFactory. It uses the terms "EE" and
"SE" for these 2 approaches, but those terms are very misleading in this context. What the JPA spec calls EE
bootstrapping is cases where a container (EE, OSGi, etc) will manage and inject the persistence context on behalf
of the application. What it calls SE bootstrapping is everything else. We will use the terms
container-bootstrapping and application-bootstrapping in this guide.
If you would like additional details on accessing and using EntityManager instances, sections 7.6
and 7.7 of the JPA 2.1 specification cover container-managed and application-managed EntityManagers,
respectively.
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Container-bootstrapping
The container will build an EntityManagerFactory for each persistent-unit defined in the deployment’s
META-INF/persistence.xml and make that available to the application for injection via the
javax.persistence.PersistenceUnit annotation or via JNDI lookup.
@PersistenceUnit
EntityManagerFactory emf;Application-bootstrapping
Rather than something a container building the EntityManagerFactory for the application, the application
can build the EntityManagerFactory using the javax.persistence.Persistence bootstrap class. The application
creates an entity manager factory by calling the createEntityManagerFactory method:
// Create an EMF for our CRM persistence-unit.
EntityManagerFactory emf = Persistence.createEntityManagerFactory("CRM");Proprietary 2-phase bootstrapping
todo: document EntityManagerFactoryBuilder…