<?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="Activities">
      <id name="farblatz" column="ACTIVITYGROUP_ID">
         <generator class="native"/>
      </id>
   
      <list name="Steps" cascade="all-delete-orphan">
            <key column="ACTIVITYGROUP_ID" not-null="true"/>
            <list-index column="stepIndex"/>
            <one-to-many class="ActivityStep" />
        </list>
      
      <property name="xxx" not-null="false"/>
      
   </class>

</hibernate-mapping>

<?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="ActivityStep" lazy="true">
      <id name="stepID">
         <generator class="native"/>
      </id>
      <discriminator column="classID"/>
      
      <many-to-one
         name="stepOwner"
         class="Activities"
         column="ACTIVITYGROUP_ID"
         not-null="true"
         insert="false"
         update="false"
      />
      <property name="Comment" not-null="false"/>
      
   </class>
   
</hibernate-mapping>

INFO  - Hibernate 3.1.2
INFO  - hibernate.properties not found
INFO  - using CGLIB reflection optimizer
INFO  - using JDK 1.4 java.sql.Timestamp handling
INFO  - configuring from file: hibernate.cfg.xml
INFO  - Reading mappings from resource: Act1.hbm.xml
INFO  - Mapping class: ActivityStep -> ActivityStep
INFO  - Reading mappings from resource: Act.hbm.xml
INFO  - Mapping class: Activities -> Activities
INFO  - Configured SessionFactory: null
INFO  - Mapping collection: Activities.Steps -> ActivityStep
INFO  - Using Hibernate built-in connection pool (not for production use!)
INFO  - Hibernate connection pool size: 20
INFO  - autocommit mode: false
INFO  - using driver: com.mysql.jdbc.Driver at URL: jdbc:mysql://mymachine/test_hibernate
INFO  - connection properties: {user=userid}
INFO  - RDBMS: MySQL, version: 5.0.15-nt
INFO  - JDBC driver: MySQL-AB JDBC Driver, version: mysql-connector-java-3.1.12 ( $Date: 2005-11-17 15:53:48 +0100 (Thu, 17 Nov 2005) $, $Revision$ )
INFO  - Using dialect: org.hibernate.dialect.MySQLInnoDBDialect
INFO  - Using default transaction strategy (direct JDBC transactions)
INFO  - No TransactionManagerLookup configured (in JTA environment, use of read-write or transactional second-level cache is not recommended)
INFO  - Automatic flush during beforeCompletion(): disabled
INFO  - Automatic session close at end of transaction: disabled
INFO  - JDBC batch size: 15
INFO  - JDBC batch updates for versioned data: disabled
INFO  - Scrollable result sets: enabled
INFO  - JDBC3 getGeneratedKeys(): enabled
INFO  - Connection release mode: auto
INFO  - Maximum outer join fetch depth: 2
INFO  - Default batch fetch size: 1
INFO  - Generate SQL with comments: enabled
INFO  - Order SQL updates by primary key: disabled
INFO  - Query translator: org.hibernate.hql.ast.ASTQueryTranslatorFactory
INFO  - Using ASTQueryTranslatorFactory
INFO  - Query language substitutions: {}
INFO  - Second-level cache: enabled
INFO  - Query cache: disabled
INFO  - Cache provider: org.hibernate.cache.EhCacheProvider
INFO  - Optimize cache for minimal puts: disabled
INFO  - Structured second-level cache entries: disabled
INFO  - Echoing all SQL to stdout
INFO  - Statistics: disabled
INFO  - Deleted entity synthetic identifier rollback: disabled
INFO  - Default entity-mode: pojo
INFO  - building session factory
WARN  - No configuration found. Configuring ehcache from ehcache-failsafe.xml found in the classpath: jar:file:/C:/hibernate-3.1/lib/ehcache-1.1.jar!/ehcache-failsafe.xml
INFO  - Not binding factory to JNDI, no JNDI name configured
INFO  - Running hbm2ddl schema export
INFO  - exporting generated schema to database
INFO  - schema export complete
Hibernate:
    /* insert Activities
        */ insert
        into
            Activities
            (xxx)
        values
            (?)
ERROR - IllegalArgumentException in class: Activities, getter method of property: farblatz
Exception in thread "main" org.hibernate.PropertyAccessException: IllegalArgumentException occurred calling getter of Activities.farblatz
   at org.hibernate.property.BasicPropertyAccessor$BasicGetter.get(BasicPropertyAccessor.java:171)
   at org.hibernate.tuple.AbstractEntityTuplizer.getIdentifier(AbstractEntityTuplizer.java:176)
   at org.hibernate.persister.entity.AbstractEntityPersister.getIdentifier(AbstractEntityPersister.java:3257)
   at org.hibernate.persister.entity.AbstractEntityPersister.isTransient(AbstractEntityPersister.java:2983)
   at org.hibernate.engine.ForeignKeys.isTransient(ForeignKeys.java:181)
   at org.hibernate.engine.ForeignKeys$Nullifier.isNullifiable(ForeignKeys.java:137)
   at org.hibernate.engine.ForeignKeys$Nullifier.nullifyTransientReferences(ForeignKeys.java:69)
   at org.hibernate.engine.ForeignKeys$Nullifier.nullifyTransientReferences(ForeignKeys.java:47)
   at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:263)
   at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:167)
   at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:101)
   at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:186)
   at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:175)
   at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:98)
   at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:70)
   at org.hibernate.impl.SessionImpl.fireSaveOrUpdate(SessionImpl.java:531)
   at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:523)
   at org.hibernate.engine.CascadingAction$1.cascade(CascadingAction.java:134)
   at org.hibernate.engine.Cascade.cascadeToOne(Cascade.java:213)
   at org.hibernate.engine.Cascade.cascadeAssociation(Cascade.java:157)
   at org.hibernate.engine.Cascade.cascadeProperty(Cascade.java:108)
   at org.hibernate.engine.Cascade.cascadeCollectionElements(Cascade.java:290)
   at org.hibernate.engine.Cascade.cascadeCollection(Cascade.java:185)
   at org.hibernate.engine.Cascade.cascadeAssociation(Cascade.java:160)
   at org.hibernate.engine.Cascade.cascadeProperty(Cascade.java:108)
   at org.hibernate.engine.Cascade.cascade(Cascade.java:248)
   at org.hibernate.event.def.AbstractSaveEventListener.cascadeAfterSave(AbstractSaveEventListener.java:410)
   at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:299)
   at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:167)
   at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:101)
   at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:186)
   at org.hibernate.event.def.DefaultSaveEventListener.saveWithGeneratedOrRequestedId(DefaultSaveEventListener.java:33)
   at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:175)
   at org.hibernate.event.def.DefaultSaveEventListener.performSaveOrUpdate(DefaultSaveEventListener.java:27)
   at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:70)
   at org.hibernate.impl.SessionImpl.fireSave(SessionImpl.java:559)
   at org.hibernate.impl.SessionImpl.save(SessionImpl.java:547)
   at org.hibernate.impl.SessionImpl.save(SessionImpl.java:543)
   at Test.<init>(Test.java:84)
   at Test.main(Test.java:106)
Caused by: java.lang.IllegalArgumentException: object is not an instance of declaring class
   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
   at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
   at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
   at java.lang.reflect.Method.invoke(Method.java:585)
   at org.hibernate.property.BasicPropertyAccessor$BasicGetter.get(BasicPropertyAccessor.java:145)
   ... 39 more

import java.util.List;
import java.util.Set;

public class Activities {
   int            farblatz;

   

   List         Steps               = null;

   int            xxx;

   public Activities() {
      super();
   }

   
   /**
    * @return the steps
    */
   public List getSteps() {
      return Steps;
   }

   /**
    * @param steps the steps to set
    */
   public void setSteps(List steps) {
      Steps = steps;
   }

   public int getFarblatz() {
      return farblatz;
   }

   /**
    * @param farblatz the farblatz to set
    */
   public void setFarblatz(int farblatz) {
      this.farblatz = farblatz;
   }

   /**
    * @return the xxx
    */
   public int getXxx() {
      return xxx;
   }

   /**
    * @param xxx the xxx to set
    */
   public void setXxx(int xxx) {
      this.xxx = xxx;
   }

}

public class ActivityStep {
   int            stepOwner         = 0;
   int            stepID            = 0;

String comment=null;
   

   public ActivityStep() {}

   
   /**
    * @return Returns the comment.
    */
   public String getComment() {
      return Comment;
   }

   /**
    * @param comment The comment to set.
    */
   public void setComment(String comment) {
      Comment = comment;
   }

   
   /**
    * @return Returns the stepID.
    */
   public int getStepID() {
      return stepID;
   }

   /**
    * @param stepID The stepID to set.
    */
   public void setStepID(int stepID) {
      this.stepID = stepID;
   }

   /**
    * @return the stepOwner
    */
   public int getStepOwner() {
      return stepOwner;
   }

   /**
    * @param stepOwner the stepOwner to set
    */
   public void setStepOwner(int stepOwner) {
      this.stepOwner = stepOwner;
   }

}