2 Replies Latest reply on Nov 6, 2009 10:57 AM by John Lennon

    javax.ejb.ConcurrentAccessException: no concurrent calls on stateful bean

    Bogdan Minciu Newbie

      Hello,


      I have 2 POJOs: Category and Page. Pages are defined in Categories. Categories also have subCategories.


      The page that displays all these associations is categories/list.xhtml. On each subCategory displayed there I have an action: #{categoryList.setParent(category)} which sets into my CategoryListBean the current parent category:


      <h:dataTable id="categories" value="#{categories}" var="category" rendered="#{categoryList.resultListSize>0}">
        <h:column>
          <f:facet name="header">ID</f:facet>
          #{category.id}
        </h:column>
        <h:column>
          <f:facet name="header">Action</f:facet>
          <s:link id="category" 
               value="Change to..." 
                view="/xcms/cms/category/list.xhtml"
              action="#{categoryList.setParent(category)}">
          </s:link>                        
        </h:column>
      </h:dataTable>
      




      @Stateful
      @Name("categoryList")
      @Scope(ScopeType.SESSION)
      @Restrict("#{identity.loggedIn}")
      public class CategoryListBean implements LocalCategoryList {
      ...
          @In
          private CategoryDAO categoryDAO;
      
          @In(required = false)
          @Out(required = false)
          private Category parent;
      
          @DataModel
          private List<Category> categories;
      
          @Factory("categories")
          @Observer("com.brit.xcms.cms.Category.categoryListModified")
          public void find() {
              categoryDAO.fillCategoriesByParent(this);
          }
      
          @RaiseEvent("com.brit.xcms.cms.Page.pageListModified")
          public void setParent(Category parent) {
              this.parent = parent;
              find();
          }
      
      ...
      }
      



      As you can see, my categoryList.setParent(category) raises an event for the PageListBean bean, to tell it that the parent from CategoryListBean has changed, so a new find must be called in order to return its pages. This is the PageListBean:


      @Stateful
      @Name("pageList")
      @Scope(ScopeType.SESSION)
      @Restrict("#{identity.loggedIn}")
      public class PageListBean implements LocalPageList {
      ...
          @In
          private PageDAO pageDAO;
      
          @Factory("pages")
          @Observer("com.brit.xcms.cms.Page.pageListModified")
          public void find() {
              pageDAO.fillPagesByParent(this);
          }
      ...
      }
      



      PageDAO:


      @Name("pageDAO")
      @AutoCreate
      public class PageDAO {
      
          @In(create = true)
          private LocalCategoryList categoryList;
      
          public void fillPagesByParent(PageListBean pageListBean) {
              Category parent = categoryList.getParent(); <------------- EXCEPTION HERE
      
              Query q = entityManager.createQuery("select p from Page p where p.category = :parent order by p.position asc").setParameter("parent", parent);
      
              pageListBean.setPages(q.getResultList());
          }
      
      }
      



      So, the problem is that when the event rises, and when the PageDAO.fillPagesByParent(PageListBean pageListBean) calls for categoryList.getParent() I get the following exception:


      javax.el.ELException: javax.ejb.EJBTransactionRolledbackException: no concurrent calls on stateful bean 'jboss.j2ee:service=EJB3,name=CategoryListBean' (EJB3 4.3.13)
              at org.jboss.el.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:333)
              at org.jboss.el.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:274)
              at org.jboss.el.parser.AstMethodSuffix.getValue(AstMethodSuffix.java:59)
              at org.jboss.el.parser.AstMethodSuffix.invoke(AstMethodSuffix.java:65)
              at org.jboss.el.parser.AstValue.invoke(AstValue.java:96)
              at org.jboss.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:276)
              at org.jboss.seam.core.Expressions$2.invoke(Expressions.java:173)
              at org.jboss.seam.navigation.Pages.callAction(Pages.java:636)
              at org.jboss.seam.navigation.Pages.preRender(Pages.java:289)
              at org.jboss.seam.jsf.SeamPhaseListener.preRenderPage(SeamPhaseListener.java:549)
              at org.jboss.seam.jsf.SeamPhaseListener.beforeRenderResponse(SeamPhaseListener.java:460)
              at org.jboss.seam.jsf.SeamPhaseListener.beforeServletPhase(SeamPhaseListener.java:144)
              at org.jboss.seam.jsf.SeamPhaseListener.beforePhase(SeamPhaseListener.java:114)
              at com.sun.faces.lifecycle.LifecycleImpl.phase(LifecycleImpl.java:222)
              at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:144)
              at javax.faces.webapp.FacesServlet.service(FacesServlet.java:245)
              at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
              at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
              at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:83)
              at org.jboss.seam.web.MultipartFilter.doFilter(MultipartFilter.java:85)
              at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
              at org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:64)
              at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
              at org.jboss.seam.web.RedirectFilter.doFilter(RedirectFilter.java:45)
              at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
              at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:141)
              at org.ajax4jsf.webapp.BaseFilter.doFilter(BaseFilter.java:281)
              at org.jboss.seam.web.Ajax4jsfFilter.doFilter(Ajax4jsfFilter.java:60)
              at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
              at org.jboss.seam.web.LoggingFilter.doFilter(LoggingFilter.java:58)
              at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
              at org.jboss.seam.debug.hot.HotDeployFilter.doFilter(HotDeployFilter.java:68)
              at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)
              at org.jboss.seam.servlet.SeamFilter.doFilter(SeamFilter.java:158)
              at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
              at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
              at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
              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:230)
              at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
              at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:179)
              at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:432)
              at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:84)
              at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
              at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
              at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:157)
              at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
              at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:262)
              at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
              at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
              at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:446)
              at java.lang.Thread.run(Thread.java:619)
      Caused by: javax.ejb.EJBTransactionRolledbackException: no concurrent calls on stateful bean 'jboss.j2ee:service=EJB3,name=CategoryListBean' (EJB3 4.3.13)
              at org.jboss.ejb3.tx.Ejb3TxPolicy.handleInCallerTx(Ejb3TxPolicy.java:87)
              at org.jboss.aspects.tx.TxPolicy.invokeInCallerTx(TxPolicy.java:130)
              at org.jboss.aspects.tx.TxInterceptor$Required.invoke(TxInterceptor.java:195)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.aspects.tx.TxPropagationInterceptor.invoke(TxPropagationInterceptor.java:95)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.ejb3.stateful.StatefulInstanceInterceptor.invoke(StatefulInstanceInterceptor.java:83)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.aspects.security.AuthenticationInterceptor.invoke(AuthenticationInterceptor.java:77)
              at org.jboss.ejb3.security.Ejb3AuthenticationInterceptor.invoke(Ejb3AuthenticationInterceptor.java:110)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagationInterceptor.java:46)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.ejb3.asynchronous.AsynchronousInterceptor.invoke(AsynchronousInterceptor.java:106)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.ejb3.stateful.StatefulContainer.localInvoke(StatefulContainer.java:206)
              at org.jboss.ejb3.stateful.StatefulLocalProxy.invoke(StatefulLocalProxy.java:119)
              at $Proxy528.find(Unknown Source)
              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:597)
              at org.jboss.seam.util.Reflections.invoke(Reflections.java:21)
              at org.jboss.seam.intercept.RootInvocationContext.proceed(RootInvocationContext.java:31)
              at org.jboss.seam.intercept.ClientSideInterceptor$1.proceed(ClientSideInterceptor.java:76)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:56)
              at org.jboss.seam.security.SecurityInterceptor.aroundInvoke(SecurityInterceptor.java:40)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.ejb.RemoveInterceptor.aroundInvoke(RemoveInterceptor.java:41)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.core.SynchronizationInterceptor.aroundInvoke(SynchronizationInterceptor.java:32)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107)
              at org.jboss.seam.intercept.ClientSideInterceptor.invoke(ClientSideInterceptor.java:54)
              at org.javassist.tmp.java.lang.Object_$$_javassist_9.find(Object_$$_javassist_9.java)
              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:597)
              at org.jboss.seam.util.Reflections.invoke(Reflections.java:21)
              at org.jboss.seam.util.Reflections.invokeAndWrap(Reflections.java:125)
              at org.jboss.seam.Component.callComponentMethod(Component.java:2082)
              at org.jboss.seam.core.Events.raiseEvent(Events.java:84)
              at org.jboss.seam.core.EventInterceptor.aroundInvoke(EventInterceptor.java:66)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.core.MethodContextInterceptor.aroundInvoke(MethodContextInterceptor.java:42)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.persistence.EntityManagerProxyInterceptor.aroundInvoke(EntityManagerProxyInterceptor.java:26)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.persistence.HibernateSessionProxyInterceptor.aroundInvoke(HibernateSessionProxyInterceptor.java:27)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107)
              at org.jboss.seam.intercept.SessionBeanInterceptor.aroundInvoke(SessionBeanInterceptor.java:50)
              at sun.reflect.GeneratedMethodAccessor1111.invoke(Unknown Source)
              at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
              at java.lang.reflect.Method.invoke(Method.java:597)
              at org.jboss.ejb3.interceptor.InvocationContextImpl.proceed(InvocationContextImpl.java:118)
              at org.jboss.ejb3.interceptor.EJB3InterceptorsInterceptor.invoke(EJB3InterceptorsInterceptor.java:63)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.ejb3.entity.ExtendedPersistenceContextPropagationInterceptor.invoke(ExtendedPersistenceContextPropagationInterceptor.java:57)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.ejb3.entity.TransactionScopedEntityManagerInterceptor.invoke(TransactionScopedEntityManagerInterceptor.java:54)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.ejb3.AllowedOperationsInterceptor.invoke(AllowedOperationsInterceptor.java:47)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.aspects.tx.TxPolicy.invokeInCallerTx(TxPolicy.java:126)
              at org.jboss.aspects.tx.TxInterceptor$Required.invoke(TxInterceptor.java:195)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.aspects.tx.TxPropagationInterceptor.invoke(TxPropagationInterceptor.java:95)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.ejb3.stateful.StatefulInstanceInterceptor.invoke(StatefulInstanceInterceptor.java:83)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.aspects.security.AuthenticationInterceptor.invoke(AuthenticationInterceptor.java:77)
              at org.jboss.ejb3.security.Ejb3AuthenticationInterceptor.invoke(Ejb3AuthenticationInterceptor.java:110)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagationInterceptor.java:46)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.ejb3.asynchronous.AsynchronousInterceptor.invoke(AsynchronousInterceptor.java:106)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.ejb3.stateful.StatefulContainer.localInvoke(StatefulContainer.java:206)
              at org.jboss.ejb3.stateful.StatefulLocalProxy.invoke(StatefulLocalProxy.java:119)
              at $Proxy526.setParent(Unknown Source)
              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:597)
              at org.jboss.seam.util.Reflections.invoke(Reflections.java:21)
              at org.jboss.seam.intercept.RootInvocationContext.proceed(RootInvocationContext.java:31)
              at org.jboss.seam.intercept.ClientSideInterceptor$1.proceed(ClientSideInterceptor.java:76)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:56)
              at org.jboss.seam.security.SecurityInterceptor.aroundInvoke(SecurityInterceptor.java:40)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.ejb.RemoveInterceptor.aroundInvoke(RemoveInterceptor.java:41)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.core.SynchronizationInterceptor.aroundInvoke(SynchronizationInterceptor.java:32)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107)
              at org.jboss.seam.intercept.ClientSideInterceptor.invoke(ClientSideInterceptor.java:54)
              at org.javassist.tmp.java.lang.Object_$$_javassist_3.setParent(Object_$$_javassist_3.java)
              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:597)
              at org.jboss.el.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:329)
              ... 52 more
      Caused by: javax.ejb.ConcurrentAccessException: no concurrent calls on stateful bean 'jboss.j2ee:service=EJB3,name=CategoryListBean' (EJB3 4.3.13)
              at org.jboss.ejb3.stateful.StatefulInstanceInterceptor.invoke(StatefulInstanceInterceptor.java:73)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.aspects.security.AuthenticationInterceptor.invoke(AuthenticationInterceptor.java:77)
              at org.jboss.ejb3.security.Ejb3AuthenticationInterceptor.invoke(Ejb3AuthenticationInterceptor.java:110)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagationInterceptor.java:46)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.ejb3.asynchronous.AsynchronousInterceptor.invoke(AsynchronousInterceptor.java:106)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.ejb3.stateful.StatefulContainer.localInvoke(StatefulContainer.java:206)
              at org.jboss.ejb3.stateful.StatefulLocalProxy.invoke(StatefulLocalProxy.java:119)
              at $Proxy526.getParent(Unknown Source)
              at sun.reflect.GeneratedMethodAccessor1162.invoke(Unknown Source)
              at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
              at java.lang.reflect.Method.invoke(Method.java:597)
              at org.jboss.seam.util.Reflections.invoke(Reflections.java:21)
              at org.jboss.seam.intercept.RootInvocationContext.proceed(RootInvocationContext.java:31)
      
              at org.jboss.seam.intercept.ClientSideInterceptor$1.proceed(ClientSideInterceptor.java:76)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:56)
              at org.jboss.seam.security.SecurityInterceptor.aroundInvoke(SecurityInterceptor.java:40)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.ejb.RemoveInterceptor.aroundInvoke(RemoveInterceptor.java:41)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.core.SynchronizationInterceptor.aroundInvoke(SynchronizationInterceptor.java:32)
      
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107)
              at org.jboss.seam.intercept.ClientSideInterceptor.invoke(ClientSideInterceptor.java:54)
              at org.javassist.tmp.java.lang.Object_$$_javassist_3.getParent(Object_$$_javassist_3.java)
              at com.brit.xcms.cms.PageDAO.fillPagesByParent(PageDAO.java:86)
              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:597)
              at org.jboss.seam.util.Reflections.invoke(Reflections.java:21)
              at org.jboss.seam.intercept.RootInvocationContext.proceed(RootInvocationContext.java:31)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:56)
              at org.jboss.seam.transaction.RollbackInterceptor.aroundInvoke(RollbackInterceptor.java:31)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.core.BijectionInterceptor.aroundInvoke(BijectionInterceptor.java:46)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.core.EventInterceptor.aroundInvoke(EventInterceptor.java:51)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.core.MethodContextInterceptor.aroundInvoke(MethodContextInterceptor.java:42)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107)
              at org.jboss.seam.intercept.JavaBeanInterceptor.interceptInvocation(JavaBeanInterceptor.java:166)
              at org.jboss.seam.intercept.JavaBeanInterceptor.invoke(JavaBeanInterceptor.java:102)
              at com.brit.xcms.cms.PageDAO_$$_javassist_10.fillPagesByParent(PageDAO_$$_javassist_10.java)
              at com.brit.xcms.cms.PageListBean.find(PageListBean.java:64)
              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:597)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:112)
              at org.jboss.ejb3.interceptor.InvocationContextImpl.proceed(InvocationContextImpl.java:166)
              at org.jboss.seam.intercept.EJBInvocationContext.proceed(EJBInvocationContext.java:44)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:56)
              at org.jboss.seam.transaction.RollbackInterceptor.aroundInvoke(RollbackInterceptor.java:31)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
      
              at org.jboss.seam.core.BijectionInterceptor.aroundInvoke(BijectionInterceptor.java:46)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.core.MethodContextInterceptor.aroundInvoke(MethodContextInterceptor.java:42)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.persistence.EntityManagerProxyInterceptor.aroundInvoke(EntityManagerProxyInterceptor.java:26)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.persistence.HibernateSessionProxyInterceptor.aroundInvoke(HibernateSessionProxyInterceptor.java:27)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.intercept.RootInterceptor.invoke(RootInterceptor.java:107)
              at org.jboss.seam.intercept.SessionBeanInterceptor.aroundInvoke(SessionBeanInterceptor.java:50)
              at sun.reflect.GeneratedMethodAccessor1111.invoke(Unknown Source)
              at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
              at java.lang.reflect.Method.invoke(Method.java:597)
              at org.jboss.ejb3.interceptor.InvocationContextImpl.proceed(InvocationContextImpl.java:118)
              at org.jboss.ejb3.interceptor.EJB3InterceptorsInterceptor.invoke(EJB3InterceptorsInterceptor.java:63)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.ejb3.entity.ExtendedPersistenceContextPropagationInterceptor.invoke(ExtendedPersistenceContextPropagationInterceptor.java:57)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.ejb3.entity.TransactionScopedEntityManagerInterceptor.invoke(TransactionScopedEntityManagerInterceptor.java:54)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.ejb3.AllowedOperationsInterceptor.invoke(AllowedOperationsInterceptor.java:47)
              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:101)
              at org.jboss.aspects.tx.TxPolicy.invokeInCallerTx(TxPolicy.java:126)
              ... 154 more
      
      



      I am really new to Seam and EJB, so I wasn't able to figure out exactly which are the concurrent calls for the injected CategoryListBean. Also, as I read on JBoss forums, the @Synchronized annotation would have no effect, since session scoped components are synchronized by default.


      Could anyone please post a hint on this?


      Thank you in advance,
      Bogdan.