Duplicate creation of JPA entity - spring

Question

I'm quite confused, I'm trying to find out why I'm getting the creation of two Customers in the database with the following code with no luck. I tried to cut all the noise from the code, I hope I didn't erased anything important for the resolution of the problem.
Here are in the following order : Entities, DAOs, Services and the SpecialService with the specialTreatment which holds the bogus behavior.
In the specialTreatment the aim is to get an existing Order with no Customer linked to it, create a new Customer, and associate it to the order.
Entities :
Order.java :
#Entity
public class Order {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "pk_id_order")
private Integer id;
// Other fields ...
#BatchFetch(value = BatchFetchType.IN)
#JoinColumn(name = "fk_id_customer", referencedColumnName = "pk_id_customer")
#ManyToOne(fetch = FetchType.LAZY, optional = false)
private Customer customer;
// Other fields ...
// Getter & setters for each field
#Override
public int hashCode() {
int hash = 7;
hash = 79 * hash + (this.id != null ? this.id.hashCode() : 0);
return hash;
}
#Override
public boolean equals(Object obj) {
if (obj == null || !(obj instanceof Order)) {
return false;
}
final Order other = (Order) obj;
if (this.id != other.id && (this.id == null || !this.id.equals(other.id))) {
return false;
}
return true;
}
}
Customer.java :
#Entity
public class Customer {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
#Column(name = "pk_id_customer")
private Integer id;
// Other fields
#OrderBy(value = "createdAt DESC")
#OneToMany(mappedBy = "customer", fetch = FetchType.LAZY)
private List<Order> orders;
#Override
public int hashCode() {
return (id != null ? id.hashCode() : 0);
}
#Override
public boolean equals(Object object) {
if (object == null || !(object instanceof Customer)) {
return false;
}
final Customer other = (Customer) object;
if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
return false;
}
return true;
}
}
DAOs :
#Repository
#Transactional
public class CustomerDao {
#PersistenceContext
protected EntityManager em;
public void create(Customer customer) {
this.em.persist(customer);
}
}
#Repository
#Transactional
public class OrderDao {
#PersistenceContext
protected EntityManager em;
public Order edit(Order order) {
return this.em.merge(order);
}
}
Services :
#Service
#Transactional
public class CustomerService {
#Autowired
private CustomerDao customerDao;
public void create(Customer customer) {
this.customerDao.create(customer);
}
}
#Service
#Transactional
public class OrderService {
#Autowired
private OrderDao orderDao;
public void edit(Order order) {
this.orderDao.edit(order);
}
}
#Service
#Transactional
public class SpecialService {
#Autowired
private CustomerService customerService;
#Autowired
private OrderService orderService;
#Transactional(propagation = Propagation.REQUIRES_NEW)
public void specialTreatment(Order order) {
Customer customer = new Customer();
// Fill customer ...
this.customerService.create(customer); // LINE X
order.setCustomer(customer); // LINE Y
this.orderService.edit(order);
}
}
Note :
When commenting line X :
- There is no customer created (as expected), the order is edited as expected
When commenting line Y :
- The customer is created as expected (only one row) but it is not linked to my Order
The code is called from a Spring MVC controller
Any advice ?