Real World Example · Introduction to Hibernate and JPA in Hibernate & JPA | Hibernate & JPA

Real World Example

ShopEase: The Project Used in This Course

All Java full stack materials on Careeroza (Spring Boot, Hibernate & JPA, Spring Security, Microservices) build the same e-commerce app, ShopEase. In this level you will map its core tables:

Entity	Fields (basic level)	Table
`Product`	id, name, description, price, stock, category, status	`products`
`Category`	id, name, slug	`categories`
`User`	id, email, fullName, role, address (embedded)	`users`
`Order`	id, orderNumber, status, totalAmount, shippingAddress, placedAt	`orders`
`OrderItem`, `CartItem`	id, productId, quantity, unitPrice	`order_items`, `cart_items`

Note: In the basic level, Product.category is a simple text column. Real relationships (@ManyToOne Category, @OneToMany order items) are covered in the medium level.

A Flipkart-Style Product Page, End to End

Browser: GET /api/products/42
     |
 ProductController  ->  ProductService  ->  ProductRepository.findById(42)
                                                 |
                                   Spring Data JPA -> EntityManager.find(Product.class, 42)
                                                 |
                                   Hibernate: select ... from products p where p.id=?
                                                 |
                                   JDBC + HikariCP -> MySQL
     <- JSON {"id":42,"name":"Boat Rockerz 450","price":1499.00,...}

@Entity
@Table(name = "products")
public class Product {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;
    private BigDecimal price;
    private Integer stock;
    // getters and setters
}

public interface ProductRepository extends JpaRepository<Product, Long> { }

@Service
public class ProductService {
    private final ProductRepository repo;
    public ProductService(ProductRepository repo) { this.repo = repo; }

    public Product getProduct(Long id) {
        return repo.findById(id).orElseThrow(() -> new ProductNotFoundException(id));
    }
}

By the end of this level you will understand every line of this code and what Hibernate does under it.