hibernate.LazyInitializationException

[boudewijn]

Hi,

I'm having trouble with a LIE, I guess it's a matter of configuring a detail, but I can't see the light...

I obtain a list of object from the database into a dataTable. When I choose one register, I pass the chosen object to a form, to be edited.
One of the fields is a List of objects (ManyToMany), which is mapped to a JSF selectManyCheckbox component. I have the converter in place for the List of objects.
Now when I save, I get the following error:

org.hibernate.LazyInitializationException: failed to lazily initialize a collection, no session or session was closed
	at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:383)
	at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:375)
	at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:368)
	at org.hibernate.collection.AbstractPersistentCollection.write(AbstractPersistentCollection.java:208)
	at org.hibernate.collection.PersistentBag.add(PersistentBag.java:297)
	at com.sun.faces.renderkit.html_basic.MenuRenderer.convertSelectManyValuesForModel(MenuRenderer.java:378)
	at com.sun.faces.renderkit.html_basic.MenuRenderer.convertSelectManyValue(MenuRenderer.java:125)
	at com.sun.faces.renderkit.html_basic.MenuRenderer.getConvertedValue(MenuRenderer.java:311)
	at javax.faces.component.UIInput.getConvertedValue(UIInput.java:1023)

The flow in which the view resides has <persistence-context />
defined, and the DAO that obtained the list of objects has @Transactional enabled. I also defined the Field as @ManyToMany(fetch = FetchType.EAGER) so that all information gets loaded when the record is retrieved.
The error is thrown when the List is actually empty, and a checked object is to be added to it.

Could anybody tell what's missing here?

Cheers Bo

Web Flow 2.2.1, JSF, Hibernate 3.5.6

[Nicolas]

Hello,

Are there any subflow involved ?
If yes, this could be helpfull:
https://jira.springframework.org/browse/SWF-360

Nicolas.

[boudewijn]

No, no subflows involved...

[quadinaros]

I had a similar problem, maybe this will help. I used the booking-faces example to build an application, and I noticed in some cases, <persistence-context/> worked as expected, and in other cases, it did not.

It turned out that all of the LazyDataModel instances, which I initialized like this:

<persistence-context/>
<var name="searchCriteria" class="org.springframework.webflow.samples.booking.SearchCriteria" />
....
<on-entry>
   <set name="flowScope.hotels" value="searchCriteria.getDataModel(bookingService)" />
</on-entry>

Had a different entity manager , which did not appear to be persistent across the flow, than other elements in the flow using the same bookingService.

I ended up doing it this way and it resolved the problem:

// I added these lines to HotelLazyDataModel:
public HotelLazyDataModel(){}
// Recall bookingService is annotated with @Service("bookingService")
// and has a @PersistenceContext annotation to define the EntityManager
@Autowired
public void setBookingService(BookingService service)
{
    bookingService = service;
}
public void setSearchCriteria(SearchCriteria criteria){...}

// and the flow was changed like this:
<var name="searchCriteria" class="org.springframework.webflow.samples.booking.SearchCriteria" />
<var name="hotelDataModel" value="org.springframework.webflow.samples.booking.HotelLazyDataModel"/>
...
<on-entry>
 <evaluate expression="hotelDataModel.setSearchCriteria(searchCriteria)"/>
...

I got the idea for the solution b/c I had an action class that had an @Autowired annotation to set the bookingService, and the action class seemed to be using the same (persistent) EntityManager as other elements of the flow
I tested it like this:

<set name="flowScope.testHotel" value="bookingService.findHotel(0)">
<evaluate expression="myAction.checkHotelInEntityManager(testHotel)/>

[boudewijn]

I've some more information:

When I have

<h:selectManyCheckbox id="formIdioma"
					value="#{searchCriteria.idiomas}" converter="#{idiomaConverter}"
					layout="lineDirection">
					<f:selectItems value="#{formReferenceData.allIdiomas}" />
				</h:selectManyCheckbox>

and searchCriteria.idiomas is not filled with dtabase data initially, the code works perfectly; searchCriteria.idiomas gets updated with the chosen fields.
However, when it gets filled with the data already in the database (even if it's an empty collection) I get the LIE

So somehow I guess the collection should be detached, but it's not quit clean to me why that is, I thought <persistence-context/> took care of this.