Hibernate exception; found two representations of the same collection

Question

While working on a Spring 3 MVC project using Hibernate, we encountered an annoying error. We are creating a carpool application. People can add routes (using the Gmap 3 plugin for jQuery) and can add waypoints to their route. In the database, a waypoint has a foreign key to a route. When trying to update a route (adding/removing waypoints and re-saving the route), we get the "found two representations of the same collection" error. We've researched the Internet but mostly the topics talk about the Play framework (we don't use that) and furthermore they talk about annotations as mapping method (while we use XML mappings). Does anyone have any idea how we can fix this? Or is this a problem in Hibernate itself?

Some code to clarify the problem:

XML mapping of the route class:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="be.kdg.teamb.model.pojo.Route" table="route">
        <id name="routeid" type="java.lang.Integer">
            <generator class="identity"/>
        </id>
        <property name="departure" not-null="true"/>
        <property name="latitude_departure" />
        <property name="longtidude_departure" />
        <property name="destination" not-null="true"/>
        <property name="latitude_destination" />
        <property name="longtidude_destination" />
        <property name="departureTime" not-null="true" type="java.util.Date" />
        <property name="startDate" not-null="true" type="java.util.Date"/>
        <property name="endDate" type="java.util.Date" />
        <many-to-one name="driver" column="userid" not-null="true" cascade="save-update" />
        <many-to-one name="defaultCar" column="carid" not-null="true" cascade="save-                update"/>
        <set name="waypoints" cascade="all,delete-orphan" inverse="true">
            <key column="routeid" on-delete="cascade" />
            <one-to-many class="be.kdg.teamb.model.pojo.Waypoint" />
        </set>
        <set name="rides" cascade="all,delete-orphan" inverse="true">
            <key column="routeid" on-delete="cascade" />
            <one-to-many class="be.kdg.teamb.model.pojo.Ride"/>
        </set>
        <set name="rules" cascade="all,delete-orphan" inverse="true">
            <key column="routeid" on-delete="cascade" />
            <one-to-many class="be.kdg.teamb.model.pojo.RouteRule" />
        </set>
    </class>
</hibernate-mapping>

XML mapping of the waypoint class:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="be.kdg.teamb.model.pojo.Waypoint" table="waypoint">
        <id name="waypointid" type="java.lang.Integer">
            <generator class="identity"/>
        </id>
        <property name="latitude" not-null="true" />
        <property name="longtidude" not-null="true" />
        <property name="address" not-null="true" />
        <many-to-one name="route" column="routeid" not-null="true" cascade="all" />
    </class>
</hibernate-mapping>

Code in our serivce:

@Override
@Transactional
public void add(String departureCoordinates, String departure, String destinationCoordinates, String destination, String coordinatesWaypoints, String namesWaypoints, String user, int carID, Date beginDate, Date endDate, Date departureTime) {

    User usr = userDao.get(user);

    Route route = new Route();

    //formaat: latitude-longtitude
    String[] coords = departureCoordinates.split(",");

    String departureLatitude = coords[0];
    String departureLongtitude = coords[1];

    coords = destinationCoordinates.split(",");

    String destinationLatitude = coords[0];
    String destinationLongtitude = coords[1];

    // add route information
    route.setDeparture(departure);
    route.setLatitude_departure(departureLatitude);
    route.setLongtidude_departure(departureLongtitude);

    route.setDestination(destination);
    route.setLatitude_destination(destinationLatitude);
    route.setLongtidude_destination(destinationLongtitude);

    route.setDriver(usr);
    route.setDefaultCar(carDao.get(carID));

    route.setStartDate(beginDate);
    route.setDepartureTime(departureTime);
    route.setEndDate(endDate);

    if (coordinatesWaypoints != null && coordinatesWaypoints.trim().length() != 0) {
        String[] waypoints = coordinatesWaypoints.split(";;;");
        String[] waypointNames = namesWaypoints.split(";;;");

        int i = 0;

        for (String waypointAddress : waypointNames) {
            String[] waypointCoord = waypoints[i].split(",");

            String waypointLat = waypointCoord[0];
            String waypointLon = waypointCoord[1];

            Waypoint waypoint = new Waypoint();

            waypoint.setAddress(waypointAddress);
            waypoint.setLatitude(waypointLat);
            waypoint.setLongtidude(waypointLon);

            route.addWaypoint(waypoint);

            i++;
        }
    }
        else{
            for (Waypoint waypoint : route.getWaypoints()) {
                waypointDao.delete(waypoint);
            }


    }

    routeDao.save(route);

    socialMediaService.post(user, "http://localhost:8080/route/detail/" + route.getRouteid(), "Posted a new route! From " + route.getDeparture() + " to " + route.getDestination(), "Posted new route!", "Carpool teamb", "Posted a new route! From " + route.getDeparture());

}

The error stacktrace:

HTTP Status 500 -

type Exception report

message

description The server encountered an internal error () that prevented it from fulfilling this request.

exception

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.hibernate.HibernateException: Found two representations of same collection: be.kdg.teamb.model.pojo.Route.waypoints
 org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:894)
 org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789)
 javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
 javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:311)
 org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:116)
 org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:101)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:182)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:173)
 org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
 org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)
 org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198)
 org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
root cause

org.hibernate.HibernateException: Found two representations of same collection: be.kdg.teamb.model.pojo.Route.waypoints
 org.hibernate.engine.Collections.processReachableCollection(Collections.java:175)
 org.hibernate.event.def.FlushVisitor.processCollection(FlushVisitor.java:60)
 org.hibernate.event.def.AbstractVisitor.processValue(AbstractVisitor.java:122)
 org.hibernate.event.def.AbstractVisitor.processValue(AbstractVisitor.java:83)
 org.hibernate.event.def.AbstractVisitor.processEntityPropertyValues(AbstractVisitor.java:77)
 org.hibernate.event.def.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:165)
 org.hibernate.event.def.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:219)
 org.hibernate.event.def.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:99)
 org.hibernate.event.def.DefaultAutoFlushEventListener.onAutoFlush(DefaultAutoFlushEventListener.java:58)
 org.hibernate.impl.SessionImpl.autoFlushIfRequired(SessionImpl.java:1185)
 org.hibernate.impl.SessionImpl.list(SessionImpl.java:1261)
 org.hibernate.impl.QueryImpl.list(QueryImpl.java:102)
 org.hibernate.impl.AbstractQueryImpl.uniqueResult(AbstractQueryImpl.java:890)
 be.kdg.teamb.model.dao.impl.UserDaoImpl.get(UserDaoImpl.java:31)
 be.kdg.teamb.model.service.impl.UserServiceImpl.get(UserServiceImpl.java:222)
 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:597)
 org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:318)
 org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
 org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
 org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:110)
 org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
 org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202)
 $Proxy33.get(Unknown Source)
 be.kdg.teamb.model.service.impl.SocialMediaServiceImpl.post(SocialMediaServiceImpl.java:36)
 be.kdg.teamb.model.service.impl.RouteServiceImpl.update(RouteServiceImpl.java:202)
 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:597)
 org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:318)
 org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:196)
 $Proxy40.update(Unknown Source)
 be.kdg.teamb.controller.RouteController.edit(RouteController.java:258)
 sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 java.lang.reflect.Method.invoke(Method.java:597)
 org.springframework.web.method.support.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:212)
 org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:126)
 org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:96)
 org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:617)
 org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:578)
 org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:80)
 org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:900)
 org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:827)
 org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
 org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:789)
 javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
 javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:311)
 org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:116)
 org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:101)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:182)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
 org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:323)
 org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:173)
 org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
 org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)
 org.springframework.orm.hibernate3.support.OpenSessionInViewFilter.doFilterInternal(OpenSessionInViewFilter.java:198)
 org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.25 logs.

Apache Tomcat/7.0.25

We also tried adding route.getWaypoints().clear(); but that didn't seem to help.

Any suggestions on what to do? If you want more information, just ask.

Answer 1

In the mapping of Waypoint class,

<many-to-one name="route" column="routeid" not-null="true" cascade="all" />

Just remove the cascade="all" and modify your mapping as below,

<many-to-one name="route" column="routeid" not-null="true"  />

Try to execute the code.

You can also refer the blog post here or a thread on the hibernate discussion forums here. Read here on the usage of cascade option in hibernate.