Hibernate - @GeneratedValue Annotation in JPA

Last Updated : 23 Apr, 2026

@GeneratedValue is a JPA annotation used to let the persistence provider automatically assign values to primary key fields. It eliminates manual ID management and ensures each entity gets a unique identifier when stored in the database.

  • Works with @Id to define and auto-generate primary keys
  • Delegates ID generation responsibility to the database or provider
  • Improves consistency and avoids errors caused by duplicate or missing IDs

Generation Strategies of @GeneratedValue Annotation

The @GeneratedValue annotation provides us with different strategies for the generation of primary keys, which are as follows : 

1. GenerationType.IDENTITY

  • Used when the database automatically generates the primary key using auto-increment for each new record.
  • Supported by MySQL, PostgreSQL, SQL Server, etc.

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;

Java 
package com.example.java_test_application;

@Entity
public class Employee {
    // on the below line creating an employee id generated value with the strategy for generation type.
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long empId;

    private String employeeName;

    private String employeeQualification;
}

Explanation: This defines an entity where the primary key is auto-generated by the database using auto-increment. It simplifies data insertion by removing manual ID handling.

2. GenerationType.SEQUENCE

  • Used when a database sequence is used to generate unique primary key values in a controlled and efficient manner.
  • Uses a database sequence (Oracle, PostgreSQL).

@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE)
private Long id;

Java 
@Entity
public class Department {
    // on the below line creating a variable for department
    
    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE)
    private Long departmentID;

    // on the below line creating a variable for department
    // name.
    private String departmentName;
}

Explanation: This defines an entity where the primary key is generated using a database sequence. It provides efficient and controlled ID generation.

3. GenerationType.TABLE

  • Uses a separate table to simulate sequences.
  • Works across all databases but has performance overhead.

@Id
@GeneratedValue(strategy = GenerationType.TABLE)
private Long id;

Java 
@Entity
public class Project {

    @Id
    @GeneratedValue(strategy = GenerationType.TABLE)
    private Long projectId;

    private String projectName;
}

Explanation: This defines a Project entity where projectId is generated using a separate table to manage ID values. It is database-independent but may be slower due to extra table operations.

4. GenerationType.AUTO (Default)

Lets the JPA provider choose the best strategy based on the database.

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;

Java 
@Entity
public class Product {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long productId;

    private String productName;
}

Explanation: This defines a Product entity where the primary key strategy is automatically chosen by the JPA provider based on the database. It provides flexibility and reduces manual configuration.

5. GenerationType.UUID 

  • GenerationType.UUID is not available in older JPA versions (like JPA 2.x).
  • It is introduced in Jakarta Persistence 3.1 and supported by providers like Hibernate 6.

@Id
@GeneratedValue(strategy = GenerationType.UUID)
private String id; // Stored as VARCHAR(36) or BINARY(16)

Java 
@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.UUID)
    private String
        userId; // e.g.,
                // "123e4567-e89b-12d3-a456-426614174000"

    private String username;
}

Explanation: This defines an entity where the primary key is generated as a UUID. It ensures global uniqueness, making it suitable for distributed systems.

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