Java Hibernate @OneToMany Criteria Projections returning NULL

Question

I have One to many relationship Owner->Dog. I am to query the dog by ID as well bring the Owner in EAGER way I have set this code using Hibernate 4.1.6 not XML mapping is used. i only need some fields from DOG and OWNER using Projections the SQL being generated by Hibernate is perfect but my objects is not being populate because DOG is returning the fields populated but owner is returned `DOG.OWNER==NULL` here is the code i am using so far... My `entities.other` code is omit by brevity ``` @Entity public class Owner implements Serializable { Setdogs=new HashSet(0); @OneToMany(fetch=FetchType.LAZY, mappedBy="owner") public Set getDogs(){return this.dogs} } @Entity public class Dog implements Serializable { private Owner owner; @ManyToOne(fetch=FetchType.LAZY) @JoinColumn(name="ownerid") public Owner getOwner(){return this.owner;} } ``` here is my method. ``` public Dog getDogAndOwnerById(Integer dogId) { Projection p=Projections.projectionList() .add(Projections.proper…

Accepted Answer

i follow this post Complex Hibernate Projections and as result i write my own Transformer because resultTransformer alias to bean in hibernate in one level deep.

here is my simple resultTransformer

```
public class MyOwnTransformer implements ResultTransformer
{
 @Override//the same order in projection list properties is the same returned by data array...  
 public Dog transformTuple(Object[]data,String[]alias)
 {return new Dog((Integer)data[0],new Owner((Integer)data[1]));} 
 @Override
 public List transformList(List dogs){return dogs;}//nothing to do here....
 }
```

and in my criteria i fix the code like this.

```
public Dog getDogAndOwnerById(Integer dogId) 
{
  Projection p=Projections.projectionList()
  .add(Projections.property("d.id"))//i dont need the alias anymore..
  .add(Projections.property("o.id"));
  Session session = getHibernateTemplate().getSessionFactory().openSession();        
  Criteria like = session.createCriteria(Dog.class,"d")
  .add(Restrictions.idEq(dogId)).setProjection(p)

.setResultTransformer(new MyOwnTransformer())

.setFetchMode("owner",FetchMode.JOIN).createAlias("owner","o");        
  Dog dog = (Dog)like.uniqueResult();        
  session.close();
  return dog;
}    
```

i hope it helps somebody.

Java Hibernate @OneToMany Criteria Projections returning NULL

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