Hi,

I can fetch join lazy relation that returns single result, but for collection it doesn't work correctly.

I have Attribute.java:

@Entity
public class Attribute implements Serializable {

 private Long id;

 private List<Resource> resources = new ArrayList<Resource>();

 public Attribute() {
 super();
 }

 @Id
 @GeneratedValue
 public Long getId() {
 return id;
 }

 public void setId(Long id) {
 this.id = id;
 }


 @ManyToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY)
 public List<Resource> getResources() {
 return resources;
 }
}

and Resource.java:

@Entity
public class Resource implements Serializable {
 private Long id;

 private int resourceSize = 0;

 public Resource() {
 super();
 }

 @Id
 @GeneratedValue
 public Long getId() {
 return id;
 }

 private void setId(Long id) {
 this.id = id;
 }

 public int getResourceSize() {
 return resourceSize;
 }

 public void setResourceSize(int resourceSize) {
 this.resourceSize = resourceSize;
 }
}

and a finder:

public List<Attribute> findWithResource(int resourceSize) {
 return em.createQuery(
 "SELECT ta FROM Attribute ta INNER JOIN FETCH ta.resources r" +
 " WHERE r.resourceSize = :resourceSize")
 .setParameter("resourceSize", resourceSize)
 .getResultList();
}

This should return all attributes that have resource of requested resourceSize with fetched resources.

Database content:
Attribute1: resource1 (resourceSize = 1), resource2 (resourceSize = 1), resource3 (resourceSize = 1)
Attribute2: resource1 (resourceSize = 1), resource2 (resourceSize = 1), resource3 (resourceSize = 1)

The query generated by EJB3 looks correctly:

select ...
from Attribute attribute0_
 inner join Attribute_Resource resources1_ on attribute0_.id=resources1_.Attribute_id
 inner join Resource resource2_ on resources1_.resources_id=resource2_.id
where resource2_.resourceSize=?

When I call findWithResource(1), I expect to get two Attributes, each with the three resources loaded. Instead I get six Attributes, each with three resources loaded.

I this bug inside my query, unsupported feature or bug in EJB3?

Thank you for your care, Jan