Java.Hibernate.Beginner.What about Session Fatory in Spring Boot ?

In Spring Boot, you don’t usually build or manage a SessionFactory manually. Instead, Spring Boot autoconfigures Hibernate and manages the SessionFactory for you, thanks to its integration with Spring Data JPA or the Hibernate starter.

🔹 How it works in Spring Boot:

• When you add dependencies like spring-boot-starter-data-jpa, Spring Boot:
  • Automatically creates an EntityManagerFactory (the JPA equivalent of SessionFactory).
  • Under the hood, this EntityManagerFactory is backed by Hibernate’s SessionFactory.
  • You rarely interact directly with the SessionFactory — you work with Spring Data repositories, EntityManager, or @Transactional services instead.

🔹 Getting the SessionFactory if you need it:
If you really need to access Hibernate’s native SessionFactory, you can get it from the JPA EntityManager like this:

@Autowired
private EntityManager entityManager;

public void doSomething() {
    Session session = entityManager.unwrap(Session.class);
    // Now you have direct access to the Hibernate Session.
}

Or get the SessionFactory itself:

@Autowired
private EntityManagerFactory entityManagerFactory;

public void printSessionFactoryInfo() {
    SessionFactory sessionFactory = entityManagerFactory.unwrap(SessionFactory.class);
    System.out.println("SessionFactory: " + sessionFactory);
}

🔹 Key advantages of Spring Boot integration:
✅ Handles SessionFactory lifecycle automatically — built at startup, closed on shutdown.
✅ Configures connection pool (HikariCP), dialect, caching, and more based on application.properties.
✅ Enables declarative transactions via @Transactional without manual session or transaction handling.

✅ Key takeaway:
In Spring Boot, you don’t need to create or manage SessionFactory manually — Spring Boot and Spring Data JPA abstract it away, while still giving you the option to access it if needed for advanced scenarios.