How to select an attribut that is on the "wrong" side of a OneToOne unilateral relationship with JPA criteria - jpa

Question

I've 2 entities:
#Entity
public class Customer{
#Id
#Column(name = "ID")
private Long id;
#OneToOne(mappedBy = "customer")
private Address address;
#Column(name = "FIELD_1")
private String field1;
#Column(name = "FIELD_2")
private String field2;
}
#Entity
public class Address{
#Id
#Column(name = "ID")
private Long id;
#OneToOne
#JoinColumn(name = "CUST_ID")
private Customer customer;
}
If I do a select to retrieve the Customer, the Adress is retrieved as well, all good.
But I want to do a projection and build a DTO, so only select field1 and field2 along with the Adress entity.
public class MyDTO {
private String field1;
private String field2;
private Address address;
public MyDTO (String pField1, String pField2, Adress pAddress){
field1 = pField1;
field2 = pField2;
adress = pAddress;
}
}
So I've coded that DAO method :
public List<MyDTO > getListMyDTO() {
CriteriaQuery<MyDTO > crit = builder.createQuery(MyDTO .class);
Root<Customer> root = crit.from(Customer.class);
// This is to avoid a inner join since some customer may not have an adress and i dont want to exclude them from my select
root.join("address", JoinType.LEFT);
crit.multiselect(root.get("field1"), root.get("field2"), root.get("address"));
return em.createQuery(crit).getResultList();
}
em being the entity manager.
However that doesn't work and the address ends up always null.
I sorta understand this as there is no field from root pointing to the address table, but since it works when i do a select on the entity instead of a DTO, there must be a way to make this work no?