Hi, i am having troubles with the mapping of three classes that has the following hierarchy:

Class A
Class B extends A
Class C extends A

And i have another class D that has a many-to-one asociation to the class A.
The classes A,B and C are mapped using table per subclass strategy and a discriminator column.

I try to call the method "load" from the session with the parameters D.class and the id of the row, and it gives me the right intance of D, but when i try to call the method getA() (expecting an instance of B or C depending on the value of the column) it brings an intance of a proxy that is not a subclass of B or C. Instead it is a subclass of A, so when i try to access a field on the page that belongs to any of the subclasses throws an exception because cannot find that property on the object. I am including the mapping file to see if i am doing something wrong ....

thank you and regards.

J.G.

The many-to-one in class D

<many-to-one name="infractor"
class="es.map.sgtic.sanciones.infractores.dto.Infractor"
cascade="none" outer-join="false" update="true"
insert="true" column="ID_PER_DEPAR_T"/>

Mapping file of class A,B and C:

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="es.map.sgtic.sanciones.infractores.dto.Infractor"
table="TBRSNC_INFRACTOR" discriminator-value="null" >
<id name="idInfractor" type="java.lang.Long">
<column name="ID_PER_DEPAR" not-null="true" sql-type="NUMBER"/>
<generator class="sequence">
<param name="sequence">
ID_INFRACTOR_SECUENCE
</param>
<!--
To add non XDoclet generator parameters, create a file named
hibernate-generator-params-Infractor.xml
containing the additional parameters and place it in your merge dir.
-->
</generator>
</id>
<discriminator column="LG_PERSONA" type="string" insert="false"/>
<version name="nuControl" column="NU_CONTROL" type="long"
access="property" unsaved-value="null"/>

<property name="tipoInfractor" type="java.lang.String" update="false"
insert="true">
<column name="LG_PERSONA"/>

</property>
<many-to-one name="departamento"
class="es.map.sgtic.sanciones.departamentos.dto.Departamento"
cascade="none" outer-join="false" update="true"
insert="true" column="ID_DEPSANCION"/>

<set name="expedientes" cascade="none" lazy="true" inverse="true" optimistic-lock="false" table="TBLSNC_EXPESANCION">
<key column="ID_PER_DEPAR_T"/>
<one-to-many class="es.map.sgtic.sanciones.expedientes.dto.Expediente"/>
</set>
<set name="direcciones" cascade="none" lazy="true" inverse="true" optimistic-lock="false" table="TBLSNC_EXPESANCION">
<key column="ID_PER_DEPAR"/>
<one-to-many class="es.map.sgtic.sanciones.direcciones.dto.Direccion"/>
</set>
<set name="documentosI" cascade="none" lazy="true" inverse="true" optimistic-lock="false" table="TBLSNC_EXPESANCION">
<key column="ID_PER_DEPAR"/>
<one-to-many class="es.map.sgtic.sanciones.documentoInicial.dto.DocumentoInicial"/>
</set>
<!--infractor fisico-->
<subclass name="es.map.sgtic.sanciones.infractores.dto.InfractorFisico" discriminator-value="F">
<join table="TBGSNC_INFRAFISICO">
<key not-null="true" update="false" column="ID_PER_DEPAR"/>

<property name="dni" column="DA_DNI"/>

<property name="nif" column="DA_NIF" />


<many-to-one name="nacionalidad"
class="es.map.sgtic.sanciones.nacionalidades.dto.Nacionalidad"
cascade="none" outer-join="false" update="true"
insert="true" column="CD_NACIONAD"/>


</join>
</subclass>

<subclass name="es.map.sgtic.sanciones.infractores.dto.InfractorJuridico" discriminator-value="J">
<join table="TBGSNC_INFRAJURID">
<key not-null="true" update="false" column="ID_PER_DEPAR"/>

<property name="nif" column="DA_NIF"/>

<property name="cif" column="DA_CIF"/>


<many-to-one name="infractorFisico"
class="es.map.sgtic.sanciones.infractores.dto.InfractorFisico"
cascade="none" outer-join="false" lazy="true" fetch="join" update="true"
insert="true" column="ID_PER_DEPAR_T"/>



</join></subclass>

<!--
To add non XDoclet property mappings, create a file named
hibernate-properties-Infractor.xml
containing the additional properties and place it in your merge dir.
-->
</class>
</hibernate-mapping>

Expose B and C as interfaces- those methods that you need.

This is a problem with Proxy and Polymorphism.
You can read about possible solution here:
http://www.hibernate.org/280.html