Erro Hibernate null para version

Bom dia Pessoal

Galera criei um mapeamento para uma tabela no hibernate com varios many-to-one só que agora quando do um getHibernateTemplate().flush(); ele dá o erro abaixo, nos logs do tomcat ele chega a dar um select para buscar o sequence do oracle e depois já da o erro.

[academico] ERROR [http-80-Processor24] FrameworkServlet.serviceWrapper(389) | Could not complete request java.lang.NullPointerException at net.sf.hibernate.type.IntegerType.next(IntegerType.java:52) at net.sf.hibernate.engine.Versioning.increment(Versioning.java:25) at net.sf.hibernate.impl.SessionImpl.getNextVersion(SessionImpl.java:2645) at net.sf.hibernate.impl.SessionImpl.flushEntity(SessionImpl.java:2579) at net.sf.hibernate.impl.SessionImpl.flushEntities(SessionImpl.java:2478) at net.sf.hibernate.impl.SessionImpl.flushEverything(SessionImpl.java:2280) at net.sf.hibernate.impl.SessionImpl.flush(SessionImpl.java:2259) at org.springframework.orm.hibernate.HibernateTemplate$21.doInHibernate(HibernateTemplate.java:477) at org.springframework.orm.hibernate.HibernateTemplate.execute(HibernateTemplate.java:243) at org.springframework.orm.hibernate.HibernateTemplate.flush(HibernateTemplate.java:475) at br.edu.unoesc.academico.dao.hibernate.alunoCurso.CampusDAOHibernate.saveCampus(CampusDAOHibernate.java:58) at br.edu.unoesc.academico.service.impl.alunoCurso.CampusManagerImpl.saveCampus(CampusManagerImpl.java:56) 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.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:296) at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:155) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:122) at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:56) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:144) at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:174) at $Proxy29.saveCampus(Unknown Source) at br.edu.unoesc.academico.webapp.action.alunoCurso.CampusFormController.onSubmit(CampusFormController.java:143) at org.springframework.web.servlet.mvc.SimpleFormController.processFormSubmission(SimpleFormController.java:224) at br.edu.unoesc.academico.webapp.action.BaseFormController.processFormSubmission(BaseFormController.java:462) at br.edu.unoesc.academico.webapp.action.alunoCurso.CampusFormController.processFormSubmission(CampusFormController.java:90) at org.springframework.web.servlet.mvc.AbstractFormController.handleRequestInternal(AbstractFormController.java:230) at org.springframework.web.servlet.mvc.AbstractController.handleRequest(AbstractController.java:128) at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.handle(SimpleControllerHandlerAdapter.java:44) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:584) at org.springframework.web.servlet.FrameworkServlet.serviceWrapper(FrameworkServlet.java:368) at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:328) 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.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:118) at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173) at br.edu.unoesc.academico.webapp.filter.GZIPFilter.doFilter(GZIPFilter.java:51) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173) at org.displaytag.filter.ResponseOverrideFilter.doFilter(ResponseOverrideFilter.java:125) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173) at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:75) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173) at com.opensymphony.clickstream.ClickstreamFilter.doFilter(ClickstreamFilter.java:42) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173) at br.edu.unoesc.academico.webapp.filter.ActionFilter.doFilter(ActionFilter.java:114) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173) at org.springframework.orm.hibernate.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:171) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76) 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.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:482) 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:595) [academico] ERROR [http-80-Processor24] StandardWrapperValve.invoke(260) | Servlet.service() for servlet action threw exception