Obtaining an Entity Manager Instance

JPA provides the Entity Manager API (EM), which is the main API for application developers to interact with the database. The EM manages the life cycle and state of entities. It supports create, read, update, and delete (CRUD) operations, finding entities, persisting entities, query execution, and so on.

Procedure

To obtain a container-managed EM instance, you use the @PersistenceContext annotation to have the EJB container inject an EM instance into the application component using dependency injection:
Syntax
1. ```
@PersistenceContext
public EntityManager em;
```
End of the code.
To obtain an application-managed EM instance, you must first obtain an entity manager factory instance:
Syntax
1. ```
@PersistenceUnit
EntityManagerFactory emf;
EntityManager em = emf.createEntityManager();
```
End of the code.

More Information

Entity Manager