I need help for embedded a list objects with Hibernate.

This is the Entity Message:

```
@Embeddable
public class Mensaje implements Serializable{

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    private String mensaje;

    private Usuario emisor;

    private Usuario receptor;

    //??????????????????????
    private Calendar ficha;

    private boolean leido;

}

```

This is the Entity User:

```
@Entity
@Table(name = "USUARIO")
public class Usuario implements Serializable {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "ID_USUARIO")
    private int idUsuario;

    @Column(name = "USERNAME", unique = true, nullable = false)
    private String username;

    @Column(name = "PASSWORD", nullable = false)
    private String password;

    @Column(name = "CORREO", nullable = false)
    private String correo;

    @OneToMany(mappedBy ="usuario",cascade= CascadeType.ALL)
    private List<Curso> cursos;

    @Column(name = "PAIS")
    private String pais;

    @Column(name = "CIUDAD")
    private String ciudad;

    //????????????????????????????
    @Embedded
    List <Mensaje> mensajes;
}

```

I liked embedded the entity Mensaje in the entity Usuario with Hibernate.
I have tried with ElementoColection but I don't have a good result.
Can you help me please?
Thanks ;)