Fail to get the related entity ID for a Lazy ManyToOne Relat

[pkap]

Hi all,

I have two entities, City and Country, with accessType=AccessType.FIELD, having ManyToOne relationship:

COUNTRY ENTITY BEAN

package test.entity.bean;
import javax.persistence.*;

@Entity(access=AccessType.FIELD)
@Table(name = "COUNTRY")
public class Country implements java.io.Serializable
{
 @Id
 @Column(name="ID")

 private int id;
 @Column(name="NAME")
 private String name;

 public int getId() { return this.id; }
 public void setId(int id) { this.id = id; }

 public String getName() { return this.name; }
 public void setName(String name) { this.name = name; }
}

CITY ENTITY BEAN

package test.entity.bean;
import javax.persistence.*;

@Entity(access=AccessType.FIELD)
@Table(name = "CITY")
public class City implements java.io.Serializable
{

 @Id
 @Column(name="ID")
 private int id;

 @Column(name="NAME")
 private String name;

 @ManyToOne( targetEntity=Country.class, fetch=FetchType.LAZY )
 @JoinColumn(name = "COUNTRY", nullable = true)
 private Country country;

 public City() {}

 public int getId() { return this.id; }
 public void setId(int id) { this.id = id; }

 public String getName() { return this.name; }
 public void setName(String name) { this.name = name; }

 public Country getCountry() { return this.country; }
 public void setCountry(Country country) { this.country = country; }

}

and a client that reads city.id, city.name and city.countryId only:

REMOTE CLIENT

 ...
 City city = sb.getCity(cityId);
 System.out.println(city.getId());
 System.out.println(city.getName());
 System.out.println(city.getCountry().getId()); // <-- throws LazyInitializationException
 ...

So, when I try to access city.getCountry().getId() from remote client, I get a
org.hibernate.LazyInitializationException: could not initialize proxy - no Session Exception

The strange thing is that, if I change the entity beans accessType to AccessType.PROPERTY, then this example seems to work fine!

So my question is:
- Is this the right way to get the ID from a related entity bean in a Lazy relationship?
- If yes, why doesn't it work for AccessType=FIELD entity beans? Is it a bug?
- If no, which is the right way to do it? (of course, loading the entire related entity is not an option, since my real classes are much more complicated. I just want to get the related entity's ID only)

Note: I have some reasons to use AccessType=FIELD, so changing my EntityBeans to AccessType=PROPERTY is not an option either