What is the role of the @Entity annotation in JPA?

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@Entity Annotation

  • The @Entity annotation is used in JPA to specify that a particular class is an entity.
  • An entity represents a table in a relational database, and each instance of the entity corresponds to a row in that table.
  • By marking a class with the @Entity annotation, JPA will treat it as a database table and handle the mapping of the class’s fields to the corresponding table columns.

Key Roles of @Entity:

  1. Identification:
  2. It tells JPA that the class is an entity and that it should be mapped to a corresponding database table.
  3. Mapping to Database:
  4. Establishes a mapping between the Java class and the database table, where each instance of the entity corresponds to a row in the table.
  5. Lifecycle Management:
  6. Enables the JPA provider to manage the lifecycle of the entity instances, including persistence, removal, and updates.

Example Usage:

import javax.persistence.Entity;
import javax.persistence.Id;
@Entity  

public class User {


@Id


private Long id;


private String name;


private String email;

// Getters and setters


}

In this example:

- The @Entity annotation marks the User class as an entity.

- Instances of User will be mapped to a database table (usually named user by default).

- The @Id annotation specifies the primary key of the entity.