Hi, i'm using hibernate 3.1 with spring 2.0 (Spring & Hibernate support from MyEclipse), i can store some objects and query other but i have a relatioship of type many to one with composite id and when i try to query this object a null reference exception is raised, the strange thing is that the query is executed against the database (MySql5).

The xml files are:

Option Role Object
------------------------------------------------------
<class name="sicce.api.info.OptionRole" table="option_role" catalog="sicce">
<composite-id name="id" class="sicce.api.info.OptionRoleId">
<key-many-to-one name="role" class="sicce.api.info.Role">
<column name="ID_ROLE" />
</key-many-to-one>
<key-many-to-one name="optionSicce" class="sicce.api.info.OptionSicce">
<column name="ID_OPTION_SICCE" />
</key-many-to-one>
</composite-id>
</class>
-------------------------------------------------------

The other files are:

Role
-------------------------------------------------------
<class name="sicce.api.info.Role" table="role" catalog="sicce">
<id name="idRole" type="java.lang.Integer">
<column name="ID_ROLE" />
<generator class="increment" />
</id>
<property name="description" type="java.lang.String">
<column name="DESCRIPTION" length="20" />
</property>
<set name="optionRoles" inverse="true" >
<key>
<column name="ID_ROLE" not-null="true" />
</key>
<one-to-many class="sicce.api.info.OptionRole" />
</set>
<set name="userSicces" inverse="true">
<key>
<column name="ID_ROLE" not-null="true" />
</key>
<one-to-many class="sicce.api.info.UserSicce" />
</set>
</class>
-------------------------------------------------------

Option
-------------------------------------------------------
<class name="sicce.api.info.OptionSicce" table="option_sicce" catalog="sicce">
<id name="idOptionSicce" type="java.lang.Integer">
<column name="ID_OPTION_SICCE" />
<generator class="increment" />
</id>
<property name="description" type="java.lang.String">
<column name="DESCRIPTION" length="30" />
</property>
<property name="icon" type="java.lang.String">
<column name="ICON" />
</property>

<set name="optionRoles" inverse="true">
<key>
<column name="ID_OPTION_SICCE" not-null="true" />
</key>
<one-to-many class="sicce.api.info.OptionRole" />
</set>

</class>
--------------------------------------------------------

The exception raised is:

This is the executed query (it return rows if you execute against the db)
-----------------------------------------------------------------------------------
Hibernate: select this_.ID_ROLE as ID1_5_0_, this_.ID_OPTION_SICCE as ID2_5_0_ from sicce.option_role this_ where (1=1)
-----------------------------------------------------------------------------------

Exception
-----------------------------------------------------------------------------------
Exception in thread "main" java.lang.NullPointerException
at org.hibernate.tuple.AbstractEntityTuplizer.createProxy(AbstractEntityTuplizer.java:372)
at org.hibernate.persister.entity.AbstractEntityPersister.createProxy(AbstractEntityPersister.java:3121)
.
.
.
-----------------------------------------------------------------------------------

I didn't find any concrete answer for this in the forum or in another page, i generated the files, so what i'm missing in the configuration for this entities because for other entities i can store and retrieve objects without problems.

Regards,

gishac
Db4o Most Valued Professional

Any idea for this problem from someone of the hibernate team??? so bad that nobody answer a question in this forum.

well i solved my problem changing the mapping files and avoid using an intermediate class to represent the many-to-many association.

Role mapping

<hibernate-mapping>
<class name="sicce.api.info.Role" table="role" catalog="sicce">
<id name="idRole" type="java.lang.Integer">
<column name="ID_ROLE" />
<generator class="increment" />
</id>
<property name="description" type="java.lang.String">
<column name="DESCRIPTION" length="20" />
</property>

<set name="userSicces" inverse="true">
<key>
<column name="ID_ROLE" not-null="true" />
</key>
<one-to-many class="sicce.api.info.UserSicce" />
</set>

<set name="permissions" table="option_role" lazy="false">
<key>
<column name="ID_ROLE" not-null="true" />
</key>
<many-to-many class="sicce.api.info.OptionSicce" column="ID_OPTION_SICCE" />
</set>


</class>
</hibernate-mapping>

Permissions mapping

<hibernate-mapping>
<class name="sicce.api.info.OptionSicce" table="option_sicce" catalog="sicce">
<id name="idOptionSicce" type="java.lang.Integer">
<column name="ID_OPTION_SICCE" />
<generator class="increment" />
</id>
<property name="description" type="java.lang.String">
<column name="DESCRIPTION" length="30" />
</property>

<property name="icon" type="java.lang.String">
<column name="ICON" />
</property>

<set name="roles" inverse="true" table="option_role" >
<key>
<column name="ID_OPTION_SICCE" not-null="true" />
</key>
<many-to-many class="sicce.api.info.Role" column="ID_ROLE" />
</set>

</class>
</hibernate-mapping>

This might be a little late... but I had the same problem with a very similar setup. I would get the same null pointer exception when I went after objects in a one-to-many set (represented by an intermediate class and table). Turns out asm.jar and asm-attrs.jar were not in my classpath. When I added them the error went away!

All my mappings work perfectly right now, I just avoid the use of an intermediate class to represent the many-to-many association, and use the xml in my previous post to store the objects.