What is bean-managed persistence

by

The mechanism whereby data transfer between an entity bean’s variables and a resource manager is managed by the entity bean.

In advanced Java, specifically in the context of Enterprise JavaBeans (EJB), “bean-managed persistence” refers to a type of persistence mechanism where the developer is responsible for explicitly managing the storage and retrieval of data to and from the database for EJB entity beans. This is in contrast to “container-managed persistence,” where the EJB container automatically handles the persistence operations.

Key points about bean-managed persistence:

  1. Developer Responsibility: In bean-managed persistence, the developer is responsible for writing the code to perform database operations such as inserting, updating, and deleting records.
  2. Flexibility: Bean-managed persistence provides greater flexibility to the developer to customize the data access logic according to specific requirements.
  3. Fine-Grained Control: Developers have fine-grained control over how data is stored and retrieved, allowing them to optimize performance or implement complex data access logic.
  4. Complexity: On the flip side, bean-managed persistence can be more complex to implement compared to container-managed persistence, as it requires the developer to handle low-level database operations.

Here’s a simple example of bean-managed persistence in EJB:

java
@Entity
public class Employee implements Serializable {
@Id
private Long id;
private String name;
private double salary;

// Bean-managed persistence methods
public void insertIntoDatabase() {
// Code to insert data into the database
}

public void updateDatabase() {
// Code to update data in the database
}

public void deleteFromDatabase() {
// Code to delete data from the database
}

// Getter and setter methods
// ...
}

In the example above, the Employee entity bean has methods (insertIntoDatabase, updateDatabase, deleteFromDatabase) that the developer must implement to manage the persistence of the Employee entity. This is in contrast to container-managed persistence, where these operations are automatically handled by the EJB container based on declarative metadata.

It’s worth noting that, in modern Java EE (Enterprise Edition) and Jakarta EE, the emphasis has shifted toward using more lightweight and flexible technologies like JPA (Java Persistence API) for persistence, which often abstracts away many of the complexities of bean-managed persistence.