<hibernate-mapping>
    < class  name="bo.CurrentProcess" table="CMA_CURRENT_PROCESSES">

        <id name="id" column="ID" type="java.lang.Long">
             <generator   class ="native"/>
        </id>
        ...
          <joined-subclass name="bo.RegistrationPersonProcess"   
                                                table="REGISTRATION_PERSON_PROCESSES">
            <key column="ID"/>
            <many-to-one name="registrablePerson" column="REGISTRABLE_PERSON_ID"/>
           
        </joined-subclass>
    </ class >

 public   class  RegistrationCompanyProcess
{
  Company registrableCompany;
}

   <mapping resource="bo/CurrentProcess.hbm.xml"/>

  <!--<mapping resource="bo/RegistrationPersonProcess.hbm.xml"/>-->

   public   class  Person  implements  java.io.Serializable
{
      private  Set registrationProcesses
}

  <hibernate-mapping>
    < class  name="bo.Person" table="PERSONS">
   ...
    <set name="registrationProcesses" inverse="true">
            <key column="REGISTRABLE_PERSON_NR" not- null ="false"/>
            <one-to-many  class ="bo.RegistrationPersonProcess"/>
        </set>
  </ class >

  java:hibernate/SessionFactory<-org.dom4j.tree.DefaultAttribute@170a4d0 [Attribute: name resource value "bo/RegistrationCompanyProcess.hbm.xml"]

[Configuration] Reading mappings from resource: bo/RegistrationCompanyProcess.hbm.xml

ERROR [HibernateUtil] Initial SessionFactory creation failed.
org.hibernate.MappingException: Resource: bo/RegistrationCompanyProcess.hbm.xml not found

<hibernate-mapping>
    < class  name="bo.CurrentProcess" table="CURRENT_PROCESSES" polymorphism="implicit">

        <id name="id" column="ID" type="java.lang.Long">
            <generator  class ="sequence">
                <param name="sequence">CURRENT_PROCESSES_SEQUENCE</param>
            </generator>
       </id>
        .....
        <joined-subclass namebo.RegistrationPersonProcess" table="PERSON_PROCESSES">
            <key column="ID" foreign-key="RPP_CPR_FK"/>
            <many-to-one name="registrablePerson" column="REGISTRABLE_PERSON_NR"/>
            <set name="interviewProcesses" inverse="true">
                <key column="REGISTRATION_PROCESS_ID"/>
                <one-to-many class="bo.InterviewProcess"/>
            </set>
        </joined-subclass>

        <joined-subclass name="bo.InterviewProcess" table="INTERVIEW_PROCESSES">
            <key column="ID"/>
            <many-to-one name="registrationPersonProcess" column="REGISTRATION_PROCESS_ID"/>
            <set name="interviewReports" inverse="true">
                <key column="INTERVIEW_PROCESS_ID"/>
                <one-to-many class="bo.InterviewReport"/>
            </set>
        </joined-subclass>

        <joined-subclass name="bo.RegistrationCompanyProcess" table="COMPANY_PROCESSES">
            <key column="ID"/>
            <many-to-one name="registrableCompany" column="REGISTRABLE_COMPANY_ID" not-null="false"/>
        </joined-subclass>
</ class >
</hibernate-mapping>

 public   abstract   class  CurrentProcess   implements  Serializable
{
     private   Long  id;
    ...
}

   public   class  RegistrationPersonProcess  extends  CurrentProcess
{
    private    Person registrablePerson;
    private  Set interviewProcesses;
}

 public   class  InterviewProcess  extends  CurrentProcess
{
    RegistrationPersonProcess registrationPersonProcess;
    Set interviewReports;
}