hibernate-upgrade

Hibernate 5 to 6 Upgrade Skill

Overview

Spring Boot 3 uses Hibernate 6, which includes significant changes from Hibernate 5. This skill covers the key migration considerations.

Key Changes

1. Package Namespace

Hibernate 6 uses Jakarta Persistence:

// Before (Hibernate 5)
import javax.persistence.*;
import org.hibernate.annotations.*;

// After (Hibernate 6)
import jakarta.persistence.*;
import org.hibernate.annotations.*;

2. ID Generation Strategies

Hibernate 6 changed the default ID generation strategy:

// Recommended approach for cross-database compatibility
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;

// Or using sequences (preferred for some databases)
@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "user_seq")
@SequenceGenerator(name = "user_seq", sequenceName = "user_sequence", allocationSize = 1)
private Long id;

3. Dialect Configuration

Hibernate 6 can auto-detect dialects in most cases:

# Before (often required in Hibernate 5)
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect

# After (Hibernate 6) - often can be removed