What is persistence XML used for?
The persistence. xml configuration file is used to configure a given JPA Persistence Unit. The Persistence Unit defines all the metadata required to bootstrap an EntityManagerFactory , like entity mappings, data source, and transaction settings, as well as JPA provider configuration properties.
What is persistence context and persistence unit?
3 Answers. 3. 78. PersistenceUnit injects an EntityManagerFactory , and PersistenceContext injects an EntityManager . It’s generally better to use PersistenceContext unless you really need to manage the EntityManager lifecycle manually.
What is SessionFactory in Hibernate?
SessionFactory is an Interface which is present in org. hibernate package and it is used to create Session Object. It is immutable and thread-safe in nature. buildSessionFactory() method gathers the meta-data which is in the cfg Object.
What is a persistence provider?
A persistence provider refers to an implementation of the Java Persistence API . The persistence provider is a library that provides the functionality to persist objects in the application.
What is @persistencecontext in JPA?
Today we are going to dig into the @PersistenceContext annotation, widely used by JPA/Hibernate developers to inject an Entity Manager into their DAO classes. If you’ve missed the first article about Spring @Transactional, have a look here: Spring @Transactional explained
How to define the persistence unit of entitymanagerfactory?
You only need a persistence element as the root element and a persistence-unit element with a name attribute. The attribute is used to identify the persistence unit, and you can use it during the bootstrapping process to instantiate a specific EntityManagerFactory.
What is the persistence XML file?
The persistence.xml file defines one or more persistence units, and you can configure things like: several provider-specific configuration parameters. As you can see, you can configure a lot of things in this file. But don’t worry, it isn’t as complex or overwhelming as you might expect.
How to exclude managed classes from the persistence-unit?
To do that, you first need to use one or more class elements to explicitly specify which managed classes shall be part of the persistence-unit. In the next step, you can use the exclude-unlisted-classes element to exclude all classes from the persistence-unit which were not explicitly included.