title: Error accessing field xxx by reflection for persistent property
body: <p>I don't know what's up. My jpa mapping seems fine, yet I get this error :</p>
  
  <blockquote>
    <p>Error accessing field [private main.java.entities.User
    main.java.entities.GPSCoordinates.user] by reflection for persistent
    property [main.java.entities.GPSCoordinates#user] :
    main.java.entities.GPSCoordinates</p>
  </blockquote>
  
  <pre><code>Caused by: javax.persistence.PersistenceException: org.hibernate.property.access.spi.PropertyAccessException: Error accessing field [private main.java.entities.User main.java.entities.GPSCoordinates.user] by reflection for persistent property [main.java.entities.GPSCoordinates#user] : main.java.entities.GPSCoordinates@1
      at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1692)
      at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1602)
      at org.hibernate.jpa.internal.QueryImpl.getSingleResult(QueryImpl.java:560)
      at main.java.lookup.UserServiceImp.findByUuid
  </code></pre>
  
  <p>User class: </p>
  
  <pre><code>@Entity
  @Table
  @NamedQuery(name = "User.findByUuid", query = "SELECT u FROM User u WHERE u.uuid=:uuid")
  public class User implements Serializable, PictureHolder {
      //...
      @OneToOne(mappedBy = "user", fetch = FetchType.LAZY, cascade = CascadeType.PERSIST)
      private GPSCoordinates coordinates;
  
      public GPSCoordinates getCoordinates() { return coordinates;}
      public void setCoordinates(GPSCoordinates coordinates) {this.coordinates = coordinates;}
  }
  </code></pre>
  
  <p>GPSCoordinates class:</p>
  
  <pre><code>@Entity
  @Table(name="user_gps_coordinates")
  public class GPSCoordinates implements Serializable{
  
      @Id
      @OneToOne
      @JoinColumn(name="user")
      private User user;
  
      public User getUser() { return user; }
      public void setUser(User user) {this.user = user;}
  }
  </code></pre>