LazyInitializationException

ts5366 · **Joined:** Sun May 28, 2006 9:48 pm **Posts:** 2

When i execute this criteria, it throw LazyInitializationException. but i have already set the fetchMode to JOIN. so how to solve this program?

I am using Spring to manage the Hibernate session.

Code:

private List getUsers(final Date start,final Date end){
    return (List)getHibernateTemplate().execute(new HibernateCallback()
    {         
public Object doInHibernate(Session session) throws HibernateException{      

Criteria c = session.createCriteria(Users.class)
         .setFetchMode("availability", FetchMode.JOIN)
         .createCriteria("availability")
                           .add(Restrictions.ge("dateTime",start))
            .add(Restrictions.le("dateTime",end));

return c.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY).list();
               }
            });      
   }

thanks

batmat · **Posted:** Thu Jul 06, 2006 4:29 pm

Your code seems a bit complicated to me... I've already heard about Spring templates, but if it's the normal use, then I understand why so much people are reluctant to use it and even don't recommend trying to do it...

If your dao implements DaoSupport, then you have access to getHibernateTemplate(), or more simply to getSession().

We don't use HibTemplates, but our daos are like yours managed with Spring and the only thing we use is the getSession() method. Your code would look like :

Code:

private List getUsers(final Date start,final Date end){
   Session s = getSession();
   Criteria c = session.createCriteria(Users.class)
         .setFetchMode("availability", FetchMode.JOIN)
         .createCriteria("availability")
                           .add(Restrictions.ge("dateTime",start))
            .add(Restrictions.le("dateTime",end));

    return c.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY).list();      
   } 

What is the big point of interest of using the code you gave instead of mine without HibernateCallack or HibTemplate ?

To finish, when you say that this code throw an exception, could you be a bit more precise : which line is triggering it ?

ts5366 · **Joined:** Sun May 28, 2006 9:48 pm **Posts:** 2

In my code, when i try to get the property of the availability class, it throws exception. like:

Code:

       List users=this.getUsers(start,end);    //this line do the hibernate query   
       for(int i=0;i<users.size;i++)
       {
             Users  user=users.get(i);
             Availability avail= user.getavailability();    //throw lazy exceptions
             system.out.println(avail.getName);
       }

i am not sure why these happen. because i have already set

Code:

.setFetchMode("availability", FetchMode.JOIN)

thanks.

tony

batmat · **Posted:** Fri Jul 07, 2006 2:18 am

Could you give precisions about the relations between your objects : your Availability Object contains a set of User or is the contrary ? How did you map it ?

drzoidbergh · **Joined:** Thu Apr 27, 2006 5:51 am **Posts:** 5

Whithout using Spring we encountered the same problem.

To me it seems Hibernate works on criteria queries like this:
Your criteria query retrieves your user objects as was your intention, using the subcriteria on availability to restrict the set of Users objects.
To populate the availability hibernate still respects the mapping setting, which probably states to lazy initialize it.

Hibernate seems to ignore the FetchMode.JOIN in the criteria query when you use .createCriteria on that assoziation. Thus your LazyInitialization upon access.

At least thats what I understood from http://www.hibernate.org/315.html.

My workaround was to use a filter. Your code would then look something like this:

Code:

private List getUsers(final Date start,final Date end){ 
    return (List)getHibernateTemplate().execute(new HibernateCallback() {          
      public Object doInHibernate(Session session) throws HibernateException{       
         session.enableFilter("myDateFilter").setParameter("startDate", start)
                                    .setParameter("endDate",end);
         Criteria c = session.createCriteria(Users.class) 
                     .setFetchMode("availability", FetchMode.JOIN);
                     
         session.disableFilter("myDateFilter")
         return c.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY).list(); 
        } 
    });       
} 

Your mapping:

Code:

   <filter-def name="myDateFilter">
      <filter-param name="startDate" type="java.util.Date"/>
      <filter-param name="endDate" type="java.util.Date"/>
   </filter-def>

   
   <set name="availability">
      [... omitted your key, many-to-one and other tags, as i don't know them...]
      <filter name="myDateFilter" condition=":startDate < dateTime and :endDate > dateTime"/>
   </set>