hibernate-mapping>
   <class name="ch.bedag.playground.B" table="B">
      <id name="idb" access="field">
         <column name="idb" not-null="true"/>
         <generator class="increment"/>
      </id>
      <timestamp name="myTimestamp" column="timestamp" access="field"/>
      <property name="myBeschreibung" column="beschreibung" access="field"/>
      <many-to-one name="a" column="a_id" access="field" />
   </class>
   <joined-subclass name="ch.bedag.playground.SubB" extends="ch.bedag.playground.B">
      <key column="idsubb" />
      <property name="myText" column="text" access="field"></property>
   </joined-subclass>
</hibernate-mapping>

            Session s = HibernateUtil.getSession();
            HibernateUtil.beginTransaction();

            SubB sb = new SubB();
            s.save(sb);
           
            sb.setBeschreibung("SubB");
            sb.setText("SubB Text");
           
            HibernateUtil.commitTransaction();
            HibernateUtil.closeSession();

Opening new Session for this thread.
Starting new database transaction in this thread.
Committing database transaction of this thread.
Hibernate: insert into B (timestamp, beschreibung, a_id, idb) values (?, ?, ?, ?)
Hibernate: insert into SubB (text, idsubb) values (?, ?)
Hibernate: update B set timestamp=?, beschreibung=?, a_id=? where idb=? and timestamp=?
Hibernate: update SubB set text=? where idsubb=?
16:48:15,214  WARN StaleObjectStateException:27 - An operation failed due to stale data
net.sf.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect) for ch.bedag.playground.SubB instance with identifier: 1
   at net.sf.hibernate.persister.AbstractEntityPersister.check(AbstractEntityPersister.java:511)
   at net.sf.hibernate.persister.NormalizedEntityPersister.update(NormalizedEntityPersister.java:691)
   at net.sf.hibernate.persister.NormalizedEntityPersister.update(NormalizedEntityPersister.java:666)
   at net.sf.hibernate.impl.ScheduledUpdate.execute(ScheduledUpdate.java:52)
   at net.sf.hibernate.impl.SessionImpl.executeAll(SessionImpl.java:2437)
   at net.sf.hibernate.impl.SessionImpl.execute(SessionImpl.java:2391)
   at net.sf.hibernate.impl.SessionImpl.flush(SessionImpl.java:2259)
   at net.sf.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:61)
   at ch.bedag.playground.HibernateUtil.commitTransaction(HibernateUtil.java:182)
   at ch.bedag.playground.SubBTest.testSubB(SubBTest.java:32)
   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:324)
   at junit.framework.TestCase.runTest(TestCase.java:154)
   at junit.framework.TestCase.runBare(TestCase.java:127)
   at junit.framework.TestResult$1.protect(TestResult.java:106)
   at junit.framework.TestResult.runProtected(TestResult.java:124)
   at junit.framework.TestResult.run(TestResult.java:109)
   at junit.framework.TestCase.run(TestCase.java:118)
   at junit.framework.TestSuite.runTest(TestSuite.java:208)
   at junit.framework.TestSuite.run(TestSuite.java:203)
   at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:421)
   at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:305)
   at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:186)
16:48:15,214 ERROR SessionImpl:2398 - Could not synchronize database state with session
net.sf.hibernate.StaleObjectStateException: Row was updated or deleted by another transaction (or unsaved-value mapping was incorrect) for ch.bedag.playground.SubB instance with identifier: 1
   at net.sf.hibernate.persister.AbstractEntityPersister.check(AbstractEntityPersister.java:511)
   at net.sf.hibernate.persister.NormalizedEntityPersister.update(NormalizedEntityPersister.java:691)
   at net.sf.hibernate.persister.NormalizedEntityPersister.update(NormalizedEntityPersister.java:666)
   at net.sf.hibernate.impl.ScheduledUpdate.execute(ScheduledUpdate.java:52)
   at net.sf.hibernate.impl.SessionImpl.executeAll(SessionImpl.java:2437)
   at net.sf.hibernate.impl.SessionImpl.execute(SessionImpl.java:2391)
   at net.sf.hibernate.impl.SessionImpl.flush(SessionImpl.java:2259)
   at net.sf.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:61)
   at ch.bedag.playground.HibernateUtil.commitTransaction(HibernateUtil.java:182)
   at ch.bedag.playground.SubBTest.testSubB(SubBTest.java:32)
   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:324)
   at junit.framework.TestCase.runTest(TestCase.java:154)
   at junit.framework.TestCase.runBare(TestCase.java:127)
   at junit.framework.TestResult$1.protect(TestResult.java:106)
   at junit.framework.TestResult.runProtected(TestResult.java:124)
   at junit.framework.TestResult.run(TestResult.java:109)
   at junit.framework.TestCase.run(TestCase.java:118)
   at junit.framework.TestSuite.runTest(TestSuite.java:208)
   at junit.framework.TestSuite.run(TestSuite.java:203)
   at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:421)
   at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:305)
   at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:186)
Tyring to rollback database transaction of this thread.
Closing Session of this thread.

Hibernate: insert into B (timestamp, beschreibung, a_id, idb) values (?, ?, ?, ?)
Hibernate: insert into SubB (text, idsubb) values (?, ?)
Hibernate: update B set timestamp=?, beschreibung=?, a_id=? where idb=? and timestamp=?
Hibernate: update SubB set text=? where idsubb=?

alter table C drop constraint FK43196A8
alter table SubB drop constraint FK277E22B8E411BD
alter table B drop constraint FK422D89B9
drop table A cascade constraints
drop table C cascade constraints
drop table SubB cascade constraints
drop table B cascade constraints
create table A (
   ida number(10,0) not null,
   timestamp date not null,
   beschreibung varchar2(255),
   primary key (ida)
)
create table C (
   idc number(10,0) not null,
   myName varchar2(255),
   primary key (idc)
)
create table SubB (
   idsubb number(10,0) not null,
   text varchar2(255),
   primary key (idsubb)
)
create table B (
   idb number(10,0) not null,
   timestamp date not null,
   beschreibung varchar2(255),
   a_id number(10,0),
   primary key (idb)
)
alter table C add constraint FK43196A8 foreign key (idc) references A
alter table SubB add constraint FK277E22B8E411BD foreign key (idsubb) references B
alter table B add constraint FK422D89B9 foreign key (a_id) references A