Hello all, I'm having trouble trying to persist an entity which ID is a generated value. This entity (A), at persistence time, has to persist in cascade another entity(B). The relationship within A and B is OneToMany, and the property related in B is part of a composite key. I'm using Eclipse, JBOSS Runtime, JPA/Hibernate Here is my code: Entity A: @Entity public class Cambios implements Serializable { private static final long serialVersionUID = 1L; @SequenceGenerator(name="CAMBIOS_GEN",sequenceName="CAMBIOS_SEQ",allocationSize=1) @Id @GeneratedValue(strategy=GenerationType.SEQUENCE, generator="CAMBIOS_GEN") @Column(name="ID_CAMBIO") private Long idCambio; //bi-directional many-to-one association to ObjetosCambio @OneToMany(cascade={CascadeType.PERSIST},mappedBy="cambios") private List<ObjetosCambio> objetosCambioList; public Cambios() { } ... } Entity B: @Entity @Table(name="OBJETOS_CAMBIO") public class ObjetosCambio implements Serializable { private static final long serialVersionUID = 1L; @EmbeddedId private ObjetosCambioPK id; //bi-directional many-to-one association to Cambios @ManyToOne @JoinColumn(name="ID_CAMBIO", insertable=false, updatable=false) private Cambios cambios; //bi-directional many-to-one association to Objetos @ManyToOne @JoinColumn(name="ID_OBJETO", insertable=false, updatable=false) private Objetos objetos; public ObjetosCambio() { } ... Entity B PK: @Embeddable public class ObjetosCambioPK implements Serializable { //default serial version id, required for serializable classes. private static final long serialVersionUID = 1L; @Column(name="ID_OBJETO") private Long idObjeto; @Column(name="ID_CAMBIO") private Long idCambio; public ObjetosCambioPK() { } Client: public String generarCambio(){ ServiceLocator serviceLocator = null; try { serviceLocator = serviceLocator.getInstance(); FachadaLocal tcLocal; tcLocal = (FachadaLocal)serviceLocator.getFacadeService("java:comp/env/negocio/Fachada"); Cambios cambio = new Cambios(); Iterator it = objetosLocal.iterator(); //OBJETOSLOCAL IS ALREADY POPULATED OUTSIDE OF THIS METHOD List<ObjetosCambio> ocList = new ArrayList(); while (it.hasNext()){ Objetos objeto = (Objetos)it.next(); ObjetosCambio objetosCambio = new ObjetosCambio(); objetosCambio.setCambios(cambio); //AT THIS TIME THIS "CAMBIO" DOES NOT HAVE ITS ID, ITS SUPPOSED TO BE GENERATED AT PERSISTENCE TIME ObjetosCambioPK ocPK = new ObjetosCambioPK(); ocPK.setIdObjeto(objeto.getIdObjeto()); objetosCambio.setId(ocPK); ocList.add(objetosCambio); } cambio.setObjetosCambioList(ocList); tcLocal.persistEntity(cambio); return "exito"; } catch (NamingException e) { // TODO e.printStackTrace(); } return null; } ERROR: 15:23:25,717 WARN [JDBCExceptionReporter] SQL Error: 1400, SQLState: 23000 15:23:25,717 ERROR [JDBCExceptionReporter] ORA-01400: no se puede realizar una inserción NULL en ("CDC"."OBJETOS_CAMBIO"."ID_CAMBIO") 15:23:25,717 WARN [JDBCExceptionReporter] SQL Error: 1400, SQLState: 23000 15:23:25,717 ERROR [JDBCExceptionReporter] ORA-01400: no se puede realizar una inserción NULL en ("CDC"."OBJETOS_CAMBIO"."ID_CAMBIO") 15:23:25,717 ERROR [AbstractFlushingEventListener] Could not synchronize database state with session org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:94) at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66) at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:275) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:266) at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:167) at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:321) at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:50) at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1027) at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:365) at org.hibernate.ejb.AbstractEntityManagerImpl$1.beforeCompletion(AbstractEntityManagerImpl.java:504) at com.arjuna.ats.internal.jta.resources.arjunacore.SynchronizationImple.beforeCompletion(SynchronizationImple.java:101) at com.arjuna.ats.arjuna.coordinator.TwoPhaseCoordinator.beforeCompletion(TwoPhaseCoordinator.java:269) at com.arjuna.ats.arjuna.coordinator.TwoPhaseCoordinator.end(TwoPhaseCoordinator.java:89) at com.arjuna.ats.arjuna.AtomicAction.commit(AtomicAction.java:177) at com.arjuna.ats.internal.jta.transaction.arjunacore.TransactionImple.commitAndDisassociate(TransactionImple.java:1423) at com.arjuna.ats.internal.jta.transaction.arjunacore.BaseTransaction.commit(BaseTransaction.java:137) at com.arjuna.ats.jbossatx.BaseTransactionManagerDelegate.commit(BaseTransactionManagerDelegate.java:75) at org.jboss.aspects.tx.TxPolicy.endTransaction(TxPolicy.java:170) at org.jboss.aspects.tx.TxPolicy.invokeInOurTx(TxPolicy.java:87) at org.jboss.aspects.tx.TxInterceptor$Required.invoke(TxInterceptor.java:190) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) at org.jboss.aspects.tx.TxPropagationInterceptor.invoke(TxPropagationInterceptor.java:76) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) at org.jboss.ejb3.tx.NullInterceptor.invoke(NullInterceptor.java:42) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) at org.jboss.ejb3.security.Ejb3AuthenticationInterceptorv2.invoke(Ejb3AuthenticationInterceptorv2.java:186) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) at org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagationInterceptor.java:41) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) at org.jboss.ejb3.BlockContainerShutdownInterceptor.invoke(BlockContainerShutdownInterceptor.java:67) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) at org.jboss.aspects.currentinvocation.CurrentInvocationInterceptor.invoke(CurrentInvocationInterceptor.java:67) at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) at org.jboss.ejb3.session.SessionSpecContainer.invoke(SessionSpecContainer.java:176) at org.jboss.ejb3.session.SessionSpecContainer.invoke(SessionSpecContainer.java:216) at org.jboss.ejb3.proxy.impl.handler.session.SessionProxyInvocationHandlerBase.invoke(SessionProxyInvocationHandlerBase.java:207) at org.jboss.ejb3.proxy.impl.handler.session.SessionProxyInvocationHandlerBase.invoke(SessionProxyInvocationHandlerBase.java:164) at $Proxy298.persistEntity(Unknown Source) at backing.SolicitudCambio.generarCambio(SolicitudCambio.java:521) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at com.sun.faces.el.MethodBindingImpl.invoke(MethodBindingImpl.java:146) at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:92) at javax.faces.component.UICommand.broadcast(UICommand.java:332) at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:287) at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:401) at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:95) at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:245) at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:110) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:213) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.myfaces.webapp.filter.ExtensionsFilter.doFilter(ExtensionsFilter.java:301) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:235) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:190) at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:92) at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126) at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:598) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447) at java.lang.Thread.run(Unknown Source) Caused by: java.sql.BatchUpdateException: ORA-01400: no se puede realizar una inserción NULL en ("CDC"."OBJETOS_CAMBIO"."ID_CAMBIO") Thanks in advance! JM.-