Spring Boot 2.7 to 3.x Migration Example

This project demonstrates key migration points when upgrading from Spring Boot 2.7 to 3.x.

Migration Aspects

1. Jakarta EE Namespace Changes

Current implementation uses javax.persistence.* which will change to jakarta.persistence.* in Spring Boot 3.x. This affects:

• Entity annotations (@Entity, @Id, @GeneratedValue)
• Validation annotations
• Servlet components
• JPA related code

2. Deprecated API Updates

Several APIs are deprecated in 2.7 and removed in 3.x:

• WebSecurityConfigurerAdapter replaced with component-based security
• CrudRepository method signatures refined
• Spring MVC configuration patterns
• ResponseEntity builder patterns
• WebMvcConfigurer implementations

3. Database Configuration Changes

Database handling updates include:

• H2 database version compatibility
• Hibernate 6.x as default ORM
• Updated dialect naming conventions
• HikariCP connection pool defaults
• Enhanced transaction management

4. Security Defaults Modifications

Security enhancements in 3.x:

• Stricter CSRF protection
• Enhanced security headers
• Updated password encoding defaults
• Modified session management
• Stronger CORS configuration requirements

Project Structure

The project includes:

• REST endpoint (/api/products)
• JPA entity (Product)
• H2 database configuration
• Service layer implementation
• Controller layer implementation

Running the Application

1. Start the application:

./gradlew bootRun

2. Access the endpoints:

• Products API: http://localhost:8080/api/products
• H2 Console: http://localhost:8080/h2-console