Need help with Hibernate? Read this first:
http://www.hibernate.org/ForumMailingli ... AskForHelp

Hibernate version:
3.2.6ga
Mapping documents:

Code between sessionFactory.openSession() and session.close():
saveOrUpdate.(object)
Full stack trace of any exception that occurs:
org.springframework.orm.hibernate3.HibernateSystemException: a different object with the same identifier value was already associated with the session: [de.mpicbg.sweng.commons.model.BillingGroupClassification#402880861edec835011eded3d85a0003]; nested exception is org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session: [de.mpicbg.sweng.commons.model.BillingGroupClassification#402880861edec835011eded3d85a0003]
org.springframework.orm.hibernate3.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:661)
org.springframework.orm.hibernate3.HibernateAccessor.convertHibernateAccessException(HibernateAccessor.java:412)
org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:424)
org.springframework.orm.hibernate3.HibernateTemplate.executeWithNativeSession(HibernateTemplate.java:374)
org.springframework.orm.hibernate3.HibernateTemplate.saveOrUpdate(HibernateTemplate.java:744)
de.mpicbg.sweng.commons.dao.hibernate.AbstractHibernateDao.saveOrUpdate(AbstractHibernateDao.java:161)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:585)
org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:310)
org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:138)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
$Proxy886.saveOrUpdate(Unknown Source)
de.mpicbg.sweng.commons.service.impl.AbstractServiceImpl.saveOrUpdate(AbstractServiceImpl.java:72)
de.mpicbg.sweng.commons.billing.service.impl.BillingEntryServiceImpl.saveOrUpdate(BillingEntryServiceImpl.java:29)
de.mpicbg.sweng.commons.billing.service.impl.BillingEntryServiceImpl.saveOrUpdate(BillingEntryServiceImpl.java:1)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:585)
org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:310)
org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:182)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:149)
org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:106)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:89)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:171)
org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
$Proxy899.saveOrUpdate(Unknown Source)
de.mpicbg.sweng.shevchenko.controller.BillingEntryFormController.onSubmit(BillingEntryFormController.java:177)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:585)
org.springframework.web.bind.annotation.support.HandlerMethodInvoker.doInvokeMethod(HandlerMethodInvoker.java:413)
org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:134)
org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:310)
org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:297)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:875)
org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:809)
org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:571)
org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:511)
javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
org.springframework.security.intercept.web.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:109)
org.springframework.security.intercept.web.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
org.springframework.security.ui.SessionFixationProtectionFilter.doFilterHttp(SessionFixationProtectionFilter.java:67)
org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
org.springframework.security.ui.ExceptionTranslationFilter.doFilterHttp(ExceptionTranslationFilter.java:101)
org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
org.springframework.security.providers.anonymous.AnonymousProcessingFilter.doFilterHttp(AnonymousProcessingFilter.java:105)
org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
org.springframework.security.ui.rememberme.RememberMeProcessingFilter.doFilterHttp(RememberMeProcessingFilter.java:116)
org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
org.springframework.security.wrapper.SecurityContextHolderAwareRequestFilter.doFilterHttp(SecurityContextHolderAwareRequestFilter.java:91)
org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
org.springframework.security.ui.AbstractProcessingFilter.doFilterHttp(AbstractProcessingFilter.java:277)
org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
org.springframework.security.ui.logout.LogoutFilter.doFilterHttp(LogoutFilter.java:89)
org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
org.springframework.security.context.HttpSessionContextIntegrationFilter.doFilterHttp(HttpSessionContextIntegrationFilter.java:235)
org.springframework.security.ui.SpringSecurityFilter.doFilter(SpringSecurityFilter.java:53)
org.springframework.security.util.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:390)
org.springframework.security.util.FilterChainProxy.doFilter(FilterChainProxy.java:175)
org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:236)
org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)

Name and version of the database you are using:
postgres 8.2


I have an issue with hibernate that purveys my hibernate development all the time. Basically I am saving a new object, to set the object up I assign a couple of other objects to it which I retrieve. I am using OpenSessionInView to handle a session object thorhgput a post in a spring page. The problem I have is that I am setting on the object being saved, two paramters - in the object graph these parameters both end up referring to one object. However when I do a hibernate query to obtain and assign these objects to the item being saved, hibernate is complaining that the two objects are different. They were obtained by different queries but in the same session. I've tried clearing out the current session but that does not help as the objects are pulled in by cascading.

It seems to me that when I do a saveOrUpdate, the objects are compared by object identity rather than equals() - is this the case? If so is there a way to say to hibernate, use equals and just pick the first one you get - only complain if there are two object which have the same id and their equals returns false. I could go through each object and manually assign the references which are the same to the same object identity but if I have a big object graph this is a major pain and often adds days and days to both mine and my colleagues development time.

Thanks, in advance, for your help.

Regards,

Neil