I am attempting to create a web application using Spring MVC, with Hibernate as its ORM layer. However, due to my inexperience with both frameworks I'm struggling.
The following code will properly display all the records I am looking for but still throw a stack trace into my logs. I'm having trouble finding thorough documentation concerning integrating Hibernate and SpringMVC (I've looked on springsource.org and read various articles on the interweb). Could anyone point out what I could be doing wrong here?
Please note that I have spent a few trying to track down answers on the internet for this, including looking at this SO question. Which was unfortunately no help.
I should also note that the ORM part of this application has been used and tested in a stand alone Java application without problems. So I believe the integration of Spring MVC and Hibernate is causing the issue.
Here is the stack trace (truncated) with the famous lazy initialization issue;
2009-03-10 12:14:50,353 [http-8084-6] ERROR org.hibernate.LazyInitializationException.<init>(LazyInitializationException.java:19) - could not initialize proxy - no Session
org.hibernate.LazyInitializationException: could not initialize proxy - no Session
at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:57)
at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:111)
at org.hibernate.proxy.pojo.cglib.CGLIBLazyInitializer.invoke(CGLIBLazyInitializer.java:150)
at com.generic.orm.generated.SearchRule$$EnhancerByCGLIB$$92abaed6.toString(<generated>)
at java.lang.String.valueOf(String.java:2827)
at java.lang.StringBuffer.append(StringBuffer.java:219)
at org.apache.commons.lang.builder.ToStringStyle.appendDetail(ToStringStyle.java:578)
at org.apache.commons.lang.builder.ToStringStyle.appendInternal(ToStringStyle.java:542)
at org.apache.commons.lang.builder.ToStringStyle.append(ToStringStyle.java:428)
at org.apache.commons.lang.builder.ToStringBuilder.append(ToStringBuilder.java:840)
at org.apache.commons.lang.builder.ReflectionToStringBuilder.appendFieldsIn(ReflectionToStringBuilder.java:606)
.....
Here is a code from my web page controller;
private List<Report> getReports() {
Session session = HibernateUtil.getSessionFactory().getCurrentSession();
session.beginTransaction();
List<Report> reports = session.createCriteria(Report.class).list();
Hibernate.initialize(reports);
session.getTransaction().commit();
return reports;
}
Which is employed on the web page using this display html;
<table border="1">
<c:forEach items="${model.reports}" var="report">
<tr>
<td><c:out value="${report.id}"/></td>
<td><c:out value="${report.username}"/></td>
<td><c:out value="${report.thresholdMet}"/></td>
<td><c:out value="${report.results}"/></td>
<td><c:out value="${report.searchRule.name}"/></td>
<td><c:out value="${report.uuid}"/></td>
</tr>
</c:forEach>
</table>
Note: That I added report.searchRule.name to test if I could get at the objects within the report object. It displays fine.
And in my applicationContext.xml;
<bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<property name="configLocation">
<value>classpath:hibernate.cfg.xml</value>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.di
From stackoverflow
-
The Hibernate.initialize(list) call doesn't initialize the target entity objects that are referenced in the collection. You would need to iterate over reports and initialize each individual object. The call to initialize reports turns a proxy collection into a concrete collection of Report proxies. Try code below:
for(Report r : reports) Hibernate.initialize(r);The blunt axe approach is to turn off lazy loading by adding
lazy="false"to your hbm classes. This might make sense if you will always iterate over the entire object every time its retrieved (make the initialization step OBE).James McMahon : Yeah I've tried this before, no joy. -
I am just guessing but from the stack trace it seems that toString is being called on SearchRule. Does SearchRule have any child objects that may not have been loaded? If SearchRule.toString was trying to get the value for an uninitialised child object that could result in the LazyInitializationException.
James McMahon : Hmm, yeah. I am using the apache common ReflectionToString to build my to strings, I will try removing those tomorrow. I saw that in the stack trace also, don't know why that didn't occur to me until you mentioned it. I think I have just been staring at this problem too long.James McMahon : Your answer is far too generous to me, more appropriate would have been "Read the stack trace, stupid". Ha.Mark : No problem, glad to help. -
I just went through this LazyInitialization marathon.
The core problem is that you're trying to access an hibernate-managed entity outside of the lifecycle of the
Session, i.e. in the web view of Spring MVC. In my case, this was aList<>@OneToManyassociation, which are lazily loaded by default.There are a few different approaches -- Mark mentioned one, where you do a "dummy" iteration over the lazy associations. You can also force eager loading, either via the configuration (class-wide) (in JPA it'd be
@Fetch(value = FetchType.EAGER)) or more specifically through the HQL. But this will prove more problematic if your lazy associations areLists.The cleanest solution I found was to use Spring's
OpenEntityManagerInViewFilter(there's anOpenSessionInViewFilterfor Hibernate) -- a simple servlet filter you drop in toweb.xml(ahead of your other servlet filters), and Spring will automatically create a thread-safe, transaction-awareSessionper-HTTP-request. No moreLazyInitializationException!James McMahon : Thanks, I haven't hit this issue yet (not sure why), but it sounds like advice that could be really useful down the road. -
Ok I am an idiot. My problem is I glanced over the stack trace but didn't really read it. Here is the full stack traces (or one of them, 3 slightly different versions show up in my logs).
org.hibernate.LazyInitializationException: could not initialize proxy - no Session at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:57) at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:111) at org.hibernate.proxy.pojo.cglib.CGLIBLazyInitializer.invoke(CGLIBLazyInitializer.java:150) at com.generic.orm.generated.SearchRule$$EnhancerByCGLIB$$de674d10.toString(<generated>) at java.lang.String.valueOf(String.java:2827) at java.lang.StringBuffer.append(StringBuffer.java:219) at org.apache.commons.lang.builder.ToStringStyle.appendDetail(ToStringStyle.java:578) at org.apache.commons.lang.builder.ToStringStyle.appendInternal(ToStringStyle.java:542) at org.apache.commons.lang.builder.ToStringStyle.append(ToStringStyle.java:428) at org.apache.commons.lang.builder.ToStringBuilder.append(ToStringBuilder.java:840) at org.apache.commons.lang.builder.ReflectionToStringBuilder.appendFieldsIn(ReflectionToStringBuilder.java:606) at org.apache.commons.lang.builder.ReflectionToStringBuilder.toString(ReflectionToStringBuilder.java:759) at org.apache.commons.lang.builder.ReflectionToStringBuilder.toString(ReflectionToStringBuilder.java:287) at org.apache.commons.lang.builder.ReflectionToStringBuilder.toString(ReflectionToStringBuilder.java:121) at com.generic.orm.generated.Report.toString(Report.java:141) at java.lang.String.valueOf(String.java:2827) at java.lang.StringBuilder.append(StringBuilder.java:115) at java.util.AbstractCollection.toString(AbstractCollection.java:422) at java.lang.String.valueOf(String.java:2827) at java.lang.StringBuilder.append(StringBuilder.java:115) at java.util.AbstractMap.toString(AbstractMap.java:490) at org.netbeans.modules.web.monitor.server.MonitorFilter.recordRequestAttributes(MonitorFilter.java:1376) at org.netbeans.modules.web.monitor.server.MonitorFilter.recordRequestData(MonitorFilter.java:1184) at org.netbeans.modules.web.monitor.server.MonitorFilter.getDataBefore(MonitorFilter.java:803) at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:361) 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.ApplicationDispatcher.invoke(ApplicationDispatcher.java:630) at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:436) at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:374) at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:302) at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:167) at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:239) at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1158) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:900) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:808) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:476) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:431) at javax.servlet.http.HttpServlet.service(HttpServlet.java:617) at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:390) 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:233) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447) at java.lang.Thread.run(Thread.java:619)Netbeans is apparently doing some kind of server side monitoring, which calls the toString, which freaks out because something called by the toString isn't initialized properly. So my problem is two fold, the reflection based ToString seems like a bad idea for hibernate pojos and Netbeans is changing my runtime behavior by trying to observe it.
Thanks everyone for helping, I think I had just been looking at this problem too closely for too long and needed to step back for a little.
-
Hello there,
I too have the same situation and i had configured the OpenSessionInViewFilter like this in my web.xml.
<!-- Hibernates session management for request --> <filter> <filter-name>hibReqSessionFilter</filter-name> <filter-class>org.springframework.orm.hibernate3.support.OpenSessionInViewFilter</filter-class> </filter> <filter-mapping> <filter-name>hibReqSessionFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>but still im getting the same error
[12/7/09 4:22:17:968 EST] 0000001e WebApp E [Servlet Error]-[springweb]: org.hibernate.LazyInitializationException: could not initialize proxy - no Session at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:132) at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:174) at org.hibernate.proxy.pojo.javassist.JavassistLazyInitializer.invoke(JavassistLazyInitializer.java:190) at com.moodys.mspg.model.MspgLkpAnalyst_$$_javassist_5.getAnalystId(MspgLkpAnalyst_$$_javassist_5.java) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:615) at org.apache.commons.el.ArraySuffix.evaluate(ArraySuffix.java:314) at org.apache.commons.el.ComplexValue.evaluate(ComplexValue.java:145) at org.apache.commons.el.ExpressionEvaluatorImpl.evaluate(ExpressionEvaluatorImpl.java:263) at org.apache.commons.el.ExpressionEvaluatorImpl.evaluate(ExpressionEvaluatorImpl.java:190) at org.apache.jasper.runtime.PageContextImpl.proprietaryEvaluate(PageContextImpl.java:754) at com.ibm._jsp._deallist._jspx_meth_c_out_10(_deallist.java:302) at com.ibm._jsp._deallist._jspx_meth_c_forEach_0(_deallist.java:375) at com.ibm._jsp._deallist._jspService(_deallist.java:97) at com.ibm.ws.jsp.runtime.HttpJspBase.service(HttpJspBase.java:87) at javax.servlet.http.HttpServlet.service(HttpServlet.java:856) at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1095) at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1036) at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:118) at com.ibm.ws.webcontainer.filter.WebAppFilterChain._doFilter(WebAppFilterChain.java:87) at com.ibm.ws.webcontainer.filter.WebAppFilterManager.doFilter(WebAppFilterManager.java:832) at com.ibm.ws.webcontainer.filter.WebAppFilterManager.doFilter(WebAppFilterManager.java:679) at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:565) at com.ibm.ws.wswebcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:478) at com.ibm.wsspi.webcontainer.servlet.GenericServletWrapper.handleRequest(GenericServletWrapper.java:122) at com.ibm.ws.jsp.webcontainerext.AbstractJSPExtensionServletWrapper.handleRequest(AbstractJSPExtensionServletWrapper.java:226) at com.ibm.ws.jsp.webcontainerext.AbstractJSPExtensionProcessor.handleRequest(AbstractJSPExtensionProcessor.java:285) at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.forward(WebAppRequestDispatcher.java:321) at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:236) at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:257) at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1183) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:902) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:807) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:571) at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:501) at javax.servlet.http.HttpServlet.service(HttpServlet.java:743) at javax.servlet.http.HttpServlet.service(HttpServlet.java:856) at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1095) at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1036) at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:145) at org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76) at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:190) at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:130) at com.ibm.ws.webcontainer.filter.WebAppFilterChain._doFilter(WebAppFilterChain.java:87) at com.ibm.ws.webcontainer.filter.WebAppFilterManager.doFilter(WebAppFilterManager.java:832) at com.ibm.ws.webcontainer.filter.WebAppFilterManager.doFilter(WebAppFilterManager.java:679) at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:565) at com.ibm.ws.wswebcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:478) at com.ibm.ws.webcontainer.webapp.WebApp.handleRequest(WebApp.java:3440) at com.ibm.ws.webcontainer.webapp.WebGroup.handleRequest(WebGroup.java:267) at com.ibm.ws.webcontainer.WebContainer.handleRequest(WebContainer.java:815) at com.ibm.ws.wswebcontainer.WebContainer.handleRequest(WebContainer.java:1461) at com.ibm.ws.webcontainer.channel.WCChannelLink.ready(WCChannelLink.java:118) at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleDiscrimination(HttpInboundLink.java:458) at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.handleNewInformation(HttpInboundLink.java:387) at com.ibm.ws.http.channel.inbound.impl.HttpInboundLink.ready(HttpInboundLink.java:267) at com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.sendToDiscriminators(NewConnectionInitialReadCallback.java:214) at com.ibm.ws.tcp.channel.impl.NewConnectionInitialReadCallback.complete(NewConnectionInitialReadCallback.java:113) at com.ibm.ws.tcp.channel.impl.AioReadCompletionListener.futureCompleted(AioReadCompletionListener.java:165) at com.ibm.io.async.AbstractAsyncFuture.invokeCallback(AbstractAsyncFuture.java:217) at com.ibm.io.async.AsyncChannelFuture.fireCompletionActions(AsyncChannelFuture.java:161) at com.ibm.io.async.AsyncFuture.completed(AsyncFuture.java:136) at com.ibm.io.async.ResultHandler.complete(ResultHandler.java:195) at com.ibm.io.async.ResultHandler.runEventProcessingLoop(ResultHandler.java:743) at com.ibm.io.async.ResultHandler$2.run(ResultHandler.java:873) at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1473)if i knock off this filter and use lazy="false" in my orm xmls it works as expect.
But i want the things to be lazy loaded. Could any body help me in getting this achived
many thanks in advance
James McMahon : Shivaji, I would say that the best way to get this answered is to start a separate question. LazyInitializationException seems pretty common, so I am not sure if our two issues are related at all. It has been awhile since I've dealt with Hibernate, but my advice for you is to make sure you are careful where you load your properties from your ORM object. It looks like something may be going wrong in your EL experessions.Shivaji : James, I have created a new thread. I dont think i have wrong EL because if i introduce a lazy="false" to my hbm files then it works fine.So there should be any issue with EL. I suspect i missed something else. Could you please tell me whether the filter i added was correct as expected ?
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