Estoy tratando de familiarizarme mejor con JPA, así que creé un proyecto muy simple. Tengo una clase de usuario y una clase de dirección. Parece que tengo que persistir ambos aunque estoy agregando una dirección a mi clase de usuario?

Usuario:

import javax.persistence.*;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

@Entity
@Table(name = "usr") // @Table is optional, but "user" is a keyword in many SQL variants 
@NamedQuery(name = "User.findByName", query = "select u from User u where u.name = :name")
public class User {
    @Id // @Id indicates that this it a unique primary key
    @GeneratedValue // @GeneratedValue indicates that value is automatically generated by the server
    private Long id;

    @Column(length = 32, unique = true)
    // the optional @Column allows us makes sure that the name is limited to a suitable size and is unique
    private String name;

    // note that no setter for ID is provided, Hibernate will generate the ID for us

    @OneToMany(fetch=FetchType.LAZY, mappedBy="user")
    private List<Address> addresses;

Dirección:

@Entity
public class Address {

    @Id // @Id indicates that this it a unique primary key
    @GeneratedValue // @GeneratedValue indicates that value is automatically generated by the server
    private Long id;

    @Column(length=50)
    private String address1;

    @ManyToOne
    @JoinColumn(name="user_id")
    private User user;

EntityManager:

EntityManager entityManager = Persistence.createEntityManagerFactory("tutorialPU").createEntityManager();

entityManager.getTransaction().begin();

User user = new User();
user.setName("User");

List<Address> addresses = new ArrayList<Address>();
Address address = new Address();
address.setAddress1("Address1");

addresses.add(address);
user.setAddresses(addresses);
entityManager.persist(user);
entityManager.persist(address);
entityManager.getTransaction().commit();
entityManager.close();

Probablemente haciendo algo mal ... simplemente no estoy seguro de qué es?

Cualquier sugerencia sera apreciada.

Gracias,

S