I'm getting the NullPointerException included below when my DAO calls flush(). I have no idea why... The stack trace is in checkNaturalId so I've included that part of my mapping doc below; the natural ID property and the database ID property are both set correctly. Any clues?

Hibernate version:

3.1beta3

Mapping documents:

<hibernate-mapping package="..." default-access="field">
<class name="ProjectBO" table="projects" lazy="true">
<id name="id"><generator class="native"/></id>

<natural-id mutable="false">
<property name="name" length="32" not-null="true"/>
</natural-id>

...

Full stack trace of any exception that occurs:

java.lang.NullPointerException
at org.hibernate.event.def.DefaultFlushEntityEventListener.checkNaturalId(DefaultFlushEntityEventListener.java:70)
at org.hibernate.event.def.DefaultFlushEntityEventListener.getValues(DefaultFlushEntityEventListener.java:145)
at org.hibernate.event.def.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:97)
at org.hibernate.event.def.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:195)
at org.hibernate.event.def.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:76)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:26)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:877)
at org.springframework.orm.hibernate3.HibernateTemplate$27.doInHibernate(HibernateTemplate.java:713)
at org.springframework.orm.hibernate3.HibernateTemplate.execute(HibernateTemplate.java:312)
at org.springframework.orm.hibernate3.HibernateTemplate.flush(HibernateTemplate.java:711)
at com.foo.projility.domain.BaseDAOHib.update(BaseDAOHib.java:135)
at com.foo.projility.modules.project.domain.ProjectService.updateProject(ProjectService.java:106)
at com.foo.projility.modules.project.domain.ProjectService$$FastClassByCGLIB$$9ec3bb15.invoke(<generated>)
at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149)
at org.springframework.aop.framework.Cglib2AopProxy$CglibMethodInvocation.invokeJoinpoint(Cglib2AopProxy.java:661)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:122)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:57)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:144)
at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:606)
at com.foo.projility.modules.project.domain.ProjectService$$EnhancerByCGLIB$$924524f4.updateProject(<generated>)
at com.foo.projility.modules.project.web.ProjectEditAction.execute(ProjectEditAction.java:149)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:419)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.foo.projility.web.auth.UserAuthenticationFilter.doFilter(UserAuthenticationFilter.java:80)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:856)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:744)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Thread.java:613)

Name and version of the database you are using:

Postgres 7.4.3

The generated SQL (show_sql=true):

Doesn't get as far as running any SQL...

Debug level Hibernate log excerpt:

DEBUG [http-8080-Processor23] projility.modules.project.domain.ProjectDAOHib - Update class com.foo.projility.modules.project.domain.ProjectBO: [ProjectBO: Path='/Projects/Project 13'; Name='Project 13'; Status='FUTURE'; Owner='admin'] (releases: 0) desc: project 13 desc
DEBUG [http-8080-Processor23] org.hibernate.event.def.DefaultSaveOrUpdateEventListener - updating detached instance
DEBUG [http-8080-Processor23] org.hibernate.event.def.DefaultSaveOrUpdateEventListener - updating [com.foo.projility.modules.project.domain.ProjectBO#71]
DEBUG [http-8080-Processor23] org.hibernate.event.def.DefaultSaveOrUpdateEventListener - updating [com.foo.projility.modules.project.domain.ProjectBO#71]
DEBUG [http-8080-Processor23] org.hibernate.engine.Cascade - processing cascade ACTION_SAVE_UPDATE for: com.foo.projility.modules.project.domain.ProjectBO
DEBUG [http-8080-Processor23] org.hibernate.engine.Cascade - cascade ACTION_SAVE_UPDATE for collection: com.foo.projility.modules.project.domain.ProjectBO.releases
DEBUG [http-8080-Processor23] org.hibernate.engine.Cascade - done cascade ACTION_SAVE_UPDATE for collection: com.foo.projility.modules.project.domain.ProjectBO.releases
DEBUG [http-8080-Processor23] org.hibernate.engine.Cascade - deleting orphans for collection: com.foo.projility.modules.project.domain.ProjectBO.releases
DEBUG [http-8080-Processor23] org.hibernate.engine.Cascade - done deleting orphans for collection: com.foo.projility.modules.project.domain.ProjectBO.releases
DEBUG [http-8080-Processor23] org.hibernate.engine.Cascade - done processing cascade ACTION_SAVE_UPDATE for: com.foo.projility.modules.project.domain.ProjectBO
DEBUG [Finalizer] org.hibernate.jdbc.ConnectionManager - running Session.finalize()
DEBUG [http-8080-Processor23] org.hibernate.event.def.AbstractFlushingEventListener - flushing session
DEBUG [http-8080-Processor23] org.hibernate.event.def.AbstractFlushingEventListener - processing flush-time cascades
DEBUG [http-8080-Processor23] org.hibernate.engine.Cascade - processing cascade ACTION_SAVE_UPDATE for: com.foo.projility.modules.project.domain.ProjectBO
DEBUG [http-8080-Processor23] org.hibernate.engine.Cascade - cascade ACTION_SAVE_UPDATE for collection: com.foo.projility.modules.project.domain.ProjectBO.releases
DEBUG [http-8080-Processor23] org.hibernate.engine.Cascade - done cascade ACTION_SAVE_UPDATE for collection: com.foo.projility.modules.project.domain.ProjectBO.releases
DEBUG [http-8080-Processor23] org.hibernate.engine.Cascade - deleting orphans for collection: com.foo.projility.modules.project.domain.ProjectBO.releases
DEBUG [http-8080-Processor23] org.hibernate.engine.Cascade - done deleting orphans for collection: com.foo.projility.modules.project.domain.ProjectBO.releases
DEBUG [http-8080-Processor23] org.hibernate.engine.Cascade - done processing cascade ACTION_SAVE_UPDATE for: com.foo.projility.modules.project.domain.ProjectBO
DEBUG [http-8080-Processor23] org.hibernate.event.def.AbstractFlushingEventListener - dirty checking collections
DEBUG [http-8080-Processor23] org.hibernate.event.def.AbstractFlushingEventListener - Flushing entities and processing referenced collections
DEBUG [http-8080-Processor23] org.hibernate.transaction.JDBCTransaction - rollback
DEBUG [http-8080-Processor23] org.hibernate.jdbc.JDBCContext - before transaction completion
DEBUG [http-8080-Processor23] org.hibernate.impl.SessionImpl - before transaction completion
DEBUG [http-8080-Processor23] org.hibernate.transaction.JDBCTransaction - re-enabling autocommit
DEBUG [http-8080-Processor23] org.hibernate.transaction.JDBCTransaction - rolled back JDBC Connection
DEBUG [http-8080-Processor23] org.hibernate.jdbc.JDBCContext - after transaction completion
DEBUG [http-8080-Processor23] org.hibernate.impl.SessionImpl - after transaction completion
DEBUG [http-8080-Processor23] org.hibernate.impl.SessionImpl - closing session
DEBUG [http-8080-Processor23] org.hibernate.jdbc.ConnectionManager - closing JDBC connection [ (open PreparedStatements: 0, globally: 0) (open ResultSets: 0, globally: 0)]
DEBUG [http-8080-Processor23] org.hibernate.jdbc.JDBCContext - after transaction completion
DEBUG [http-8080-Processor23] org.hibernate.impl.SessionImpl - after transaction completion
WARN [http-8080-Processor23] org.apache.struts.action.RequestProcessor - Unhandled Exception thrown: class java.lang.NullPointerException
ERROR [http-8080-Processor23] ContainerBase.[Catalina].[localhost].[/].[action] - Servlet.service() for servlet action threw exception
java.lang.NullPointerException
at org.hibernate.event.def.DefaultFlushEntityEventListener.checkNaturalId(DefaultFlushEntityEventListener.java:70)
at org.hibernate.event.def.DefaultFlushEntityEventListener.getValues(DefaultFlushEntityEventListener.java:145)
at org.hibernate.event.def.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:97)
at org.hibernate.event.def.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:195)
at org.hibernate.event.def.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:76)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:26)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:877)
at org.springframework.orm.hibernate3.HibernateTemplate$27.doInHibernate(HibernateTemplate.java:713)
at org.springframework.orm.hibernate3.HibernateTemplate.execute(HibernateTemplate.java:312)
at org.springframework.orm.hibernate3.HibernateTemplate.flush(HibernateTemplate.java:711)
at com.foo.projility.domain.BaseDAOHib.update(BaseDAOHib.java:135)
at com.foo.projility.modules.project.domain.ProjectService.updateProject(ProjectService.java:106)
at com.foo.projility.modules.project.domain.ProjectService$$FastClassByCGLIB$$9ec3bb15.invoke(<generated>)
at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149)
at org.springframework.aop.framework.Cglib2AopProxy$CglibMethodInvocation.invokeJoinpoint(Cglib2AopProxy.java:661)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:122)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:57)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:144)
at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:606)
at com.foo.projility.modules.project.domain.ProjectService$$EnhancerByCGLIB$$924524f4.updateProject(<generated>)
at com.foo.projility.modules.project.web.ProjectEditAction.execute(ProjectEditAction.java:149)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:419)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at com.foo.projility.web.auth.UserAuthenticationFilter.doFilter(UserAuthenticationFilter.java:80)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:856)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:744)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Thread.java:613)

Does anyone have any suggestions on what's going on with this? I've had to comment out the natural-id part of the mapping document to get things working, but obviously that's not ideal...

L.