Hibernate version: 3.0

Dear Hibernate Team,
We’re having a problem with join fetching. The bottom line is that after specifying the fetch=”join” in the hierarchy of objects that we need to fetch using get/load;
1. We save the Object “InvPo” with its child Set “InvPoItems” wrapped in parent.
2. After save, we use load to get the object with other associations. Load() gives the InvPo and Child Set “InvPoItems” from cache.
3. But when we access the “InvNdcLocation”, it only gives the PK of entity and throws Null Pointer Exception on accessing any other attribute.
4. Further objects in hierarchy are not accessible.
5. If not using the cache (load in second transaction), it shows the Lazy Loading Initialization Exception.

Following is the hierarchy of objects that we wish to fetch.

Entity: InvPo
<set name="invPoItemsSet" fetch="join" inverse="true" cascade="all" >
<key column="NM_PO_ID"/>
<one-to-many class="InvPoItems"/>
</set>

Entity: InvPoItems
<many-to-one name="invNdcLocation" column="NM_NDC_LOCATION_ID" class="InvNdcLocation" fetch="join" />

Entity: InvNdcLocation
<many-to-one name="invNdcListing" column="NM_NDC_LISTING_ID" class="InvNdcListing" fetch="join" />


Entity: InvNdcListing
<many-to-one name="oncDrgDetail" column="ONC_DRG_DETAIL_OID" class="OncDrgDetail" fetch="join"/>


Using .load(class, serializable) method, it is not fetching the desired objects.

Can anyone guide us on how to resolve this issue?

Thanx and Regards,
Wasif

Try adding lazy="false"
i.e.
<many-to-one name="invNdcLocation" column="NM_NDC_LOCATION_ID" class="InvNdcLocation" fetch="join" lazy="false"/>

I useed the tag lazy="false" along with fetch="join", but it is not working.

An important point is according to the article "A Short Primer On Fetching Strategies (http://www.hibernate.org/315.html)", there is no need of using lazy="false". Because, if lazy="false" is used the HQL query will retrieve extra data which is not required. Two options are available

1. lazy="false" and fetch="select"
2. fetch="join"

But option 2 is not working, even with lazy="false".


Regards,
Wasif

I have the same problem. I can verify with the generated SQL that the join is performed and looking at the debug output I see a line like this:



But after that hibernate still wants to initialize the one-to-many collections with a SQL for each parent object. Although all child objects were already initialized.

I set