CODEWITHSUNDEEP
javaspringhibernate
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CodeMed

Reputation: 9191

failed to lazily initialize a collection due to no session

In a spring mvc application using hibernate, I am getting the following error message: 

root cause  
org.hibernate.LazyInitializationException:  
failed to lazily initialize a collection of role:  
org.springframework.samples.knowledgemanager.model.Encounter.providers,  
could not initialize proxy - no Session

The error is being thrown when I try to access an arraylist that is a property of each object in another arraylist. Specifically, I have an arraylist of Encounter objects called encountersforday, and each of the Encounter objects has a property providers which is an arraylist of Provider objects. The error is thrown when I try to call the providers arraylist from the jsp using spring expression language as follows: 

<spring:eval expression="encountersforday.get(2).getProviders()" var="myps" />
<c:forEach var="id" items="${myps}" varStatus="k">//this is the line throwing error
    <spring:eval expression="id==3" var="match_id"></spring:eval>
    <c:choose>
        <c:when test="${match_id==true}">true</c:when>
        <c:otherwise>false</c:otherwise>
    </c:choose>
</c:forEach>

The code above references the following controller code: 

@RequestMapping("/calendar")
public String showCalendar(@RequestParam("day") String day, org.springframework.web.context.request.WebRequest webRequest, Model model) {
    String pid = webRequest.getParameter("pid");
    System.out.println("............ pid is:  "+pid);
    model.addAttribute("pid", pid);
    LocalDate mydate;
    if(day.equals("")){mydate = new LocalDate();}
    else{mydate = new LocalDate(day);}
    System.out.println("------------------------ in controller, day of month is:  "+mydate.getDayOfMonth());
    AppointmentCalendar calendar = new AppointmentCalendar(mydate); // Or whatever you do to create it
    List<Encounter> encountersforday = (List<Encounter>) clinicService.getEncountersForDay(mydate);
    model.addAttribute("calendar", calendar);
    model.addAttribute("encountersforday", encountersforday);
    System.out.println("number of encountersforday is: "+encountersforday.size());
    List<LocalTime> myblocks = calendar.getBlocks();
    int[][] filledblocks = new int[myblocks.size()][3];
    for(Integer i=0;i<encountersforday.size();i++){
        System.out.println("i, encounterid, patientid, first, last, dateTime are: "+i+", "+encountersforday.get(i).getId()+", "
    +encountersforday.get(i).getPatient().getId()+", "+encountersforday.get(i).getPatient().getFirstName()+", "+encountersforday.get(i).getPatient().getLastName()+", "+encountersforday.get(i).getDateTime());
        for(Integer g=0;g<myblocks.size();g++){
            filledblocks[g][0] = g;//blockid
            if(myblocks.get(g).getHourOfDay()==encountersforday.get(i).getDateTime().getHourOfDay()){
                if(myblocks.get(g).getMinuteOfHour()==encountersforday.get(i).getDateTime().getMinuteOfHour()){
                    int hours = myblocks.get(g).getHourOfDay();
                    int mins = myblocks.get(g).getMinuteOfHour();
                    System.out.println("found match at: "+hours+":"+mins);
                    filledblocks[g][1] = i+1;//encounterid
                    filledblocks[g][2] = 1;//segmentindex
                }
            }
        }
    }

    for(int k=0;k<filledblocks.length;k++){
        System.out.println("blockid, encounterid, segmentnum are: "+filledblocks[k][0]+", "+filledblocks[k][1]+", "+filledblocks[k][2]);
    }
    model.addAttribute("filledblocks", filledblocks);

//get list of providers for columns in calendar
List ps = (List) clinicService.findProvidersByFacilityAddressId(7); model.addAttribute("ps", ps); for(int g=0;g 

    return "appointments/calendar";
}

The code for the actual entities can be found on a file sharing site by clicking the following links:

The code for the Encounter entity can be found at this link.
The code for the Provider entity can be found at this link.

And here is the complete stack trace: 

Feb 21, 2014 12:39:48 PM org.apache.catalina.core.ApplicationDispatcher invoke
SEVERE: Servlet.service() for servlet jsp threw exception
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: org.springframework.samples.knowledgemanager.model.Encounter.providers, could not initialize proxy - no Session
    at org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:566)
    at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:186)
    at org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:545)
    at org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:124)
at org.hibernate.collection.internal.PersistentSet.iterator(PersistentSet.java:180)
    at org.apache.taglibs.standard.tag.common.core.ForEachSupport.toForEachIterator(ForEachSupport.java:348)
    at org.apache.taglibs.standard.tag.common.core.ForEachSupport.supportedTypeForEachIterator(ForEachSupport.java:224)
    at org.apache.taglibs.standard.tag.common.core.ForEachSupport.prepare(ForEachSupport.java:155)
    at javax.servlet.jsp.jstl.core.LoopTagSupport.doStartTag(LoopTagSupport.java:256)
    at org.apache.jsp.WEB_002dINF.jsp.appointments.calendar_jsp._jspx_meth_c_005fforEach_005f3(calendar_jsp.java:1127)
    at org.apache.jsp.WEB_002dINF.jsp.appointments.calendar_jsp._jspx_meth_c_005fotherwise_005f0(calendar_jsp.java:999)
    at org.apache.jsp.WEB_002dINF.jsp.appointments.calendar_jsp._jspx_meth_c_005fchoose_005f0(calendar_jsp.java:788)
    at org.apache.jsp.WEB_002dINF.jsp.appointments.calendar_jsp._jspx_meth_c_005fforEach_005f2(calendar_jsp.java:719)
    at org.apache.jsp.WEB_002dINF.jsp.appointments.calendar_jsp._jspx_meth_c_005fforEach_005f1(calendar_jsp.java:619)
    at org.apache.jsp.WEB_002dINF.jsp.appointments.calendar_jsp._jspService(calendar_jsp.java:192)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:749)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:487)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:412)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:339)
    at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
    at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:263)
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1208)
    at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:992)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:939)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at com.github.dandelion.datatables.core.web.filter.DatatablesFilter.doFilter(DatatablesFilter.java:73)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at com.github.dandelion.datatables.extras.servlet2.filter.DatatablesFilter.doFilter(DatatablesFilter.java:71)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)
Feb 21, 2014 12:39:48 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [KnowledgeManager] in context with path [/KnowledgeManager] threw exception [org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: org.springframework.samples.knowledgemanager.model.Encounter.providers, could not initialize proxy - no Session] with root cause
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: org.springframework.samples.knowledgemanager.model.Encounter.providers, could not initialize proxy - no Session
    at org.hibernate.collection.internal.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:566)
    at org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:186)
    at org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:545)
    at org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:124)
    at org.hibernate.collection.internal.PersistentSet.iterator(PersistentSet.java:180)
    at org.apache.taglibs.standard.tag.common.core.ForEachSupport.toForEachIterator(ForEachSupport.java:348)
    at org.apache.taglibs.standard.tag.common.core.ForEachSupport.supportedTypeForEachIterator(ForEachSupport.java:224)
    at org.apache.taglibs.standard.tag.common.core.ForEachSupport.prepare(ForEachSupport.java:155)
    at javax.servlet.jsp.jstl.core.LoopTagSupport.doStartTag(LoopTagSupport.java:256)
    at org.apache.jsp.WEB_002dINF.jsp.appointments.calendar_jsp._jspx_meth_c_005fforEach_005f3(calendar_jsp.java:1127)
    at org.apache.jsp.WEB_002dINF.jsp.appointments.calendar_jsp._jspx_meth_c_005fotherwise_005f0(calendar_jsp.java:999)
    at org.apache.jsp.WEB_002dINF.jsp.appointments.calendar_jsp._jspx_meth_c_005fchoose_005f0(calendar_jsp.java:788)
    at org.apache.jsp.WEB_002dINF.jsp.appointments.calendar_jsp._jspx_meth_c_005fforEach_005f2(calendar_jsp.java:719)
    at org.apache.jsp.WEB_002dINF.jsp.appointments.calendar_jsp._jspx_meth_c_005fforEach_005f1(calendar_jsp.java:619)
    at org.apache.jsp.WEB_002dINF.jsp.appointments.calendar_jsp._jspService(calendar_jsp.java:192)
    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:432)
    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:749)
    at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:487)
    at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:412)
    at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:339)
    at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:238)
    at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:263)
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1208)
    at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:992)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:939)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at com.github.dandelion.datatables.core.web.filter.DatatablesFilter.doFilter(DatatablesFilter.java:73)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at com.github.dandelion.datatables.extras.servlet2.filter.DatatablesFilter.doFilter(DatatablesFilter.java:71)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)

Upvotes: 2

Views: 3100

Answers (1)

Pace
Pace

Reputation: 43817

Somehow (it is not visible in the code you posted and doesn't terribly matter) your clientService is using a Session object to get the list of Encounter objects. That Session object has a close method which is called when the Session is finished. Once that close method is called, you cannot access lazily initialized properties unless they have already been initialized.

This trips up most people because most people do not actually open and close the Hibernate sessions themselves but have that taken care of by an underlying framework. For example, if you are using Spring you are likely using the @Transactional and @PersistenceContext annotations which are opening and closing sessions under the hood (in this case, the session is closed when the transaction ends, e.g. when you leave the scope of the @Transactional method).

Ultimately, however you are doing things, the solutions available are the same. The easiest solution is to simply mark the Encounter's provider relationship as an eager relationship (e.g. @ManyToMany(... fetch=FetchType.EAGER ...)) but this may have performance implications if there are lots of places you load Encounter objects and not Provider objects.

Another "global" solution would be to extend your transaction scope so that the processing of the JSP is actually inside your transaction for the request. This is often done by putting the start and stop of the transaction in filters. Although sometimes this does not work for people either.

A very targetted solution is to use the static method Hibernate.initialize() to initialize each object before you pass it to the JSP layer:

List<Encounter> encountersforday = (List<Encounter>) clinicService.getEncountersForDay(mydate);
for(Encounter encounter: encountersforday) {
    Hibernate.initialize(encounter.getProviders());
}

There may be other solutions as well, but these are the ones that jump to mind. I hope you can make progress with this.

Upvotes: 4

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