4 Replies Latest reply on Nov 6, 2009 12:26 PM by John Lennon

    ConcurrentAccessException: no concurrent calls on stateful bean

    Bogdan Minciu Newbie

      Hello guys,


      I have this CONVERSATION scoped component:


      @Stateful
      @Name("blogEntryCreate")
      @Scope(ScopeType.CONVERSATION)
      @Restrict("#{identity.loggedIn}")
      @Synchronized
      public class BlogEntryCreateBean implements LocalBlogEntryCreate {
      
      ...
          @Out(required = false)
          private BlogEntry newBlogEntry;
      
          private String body;
      
          @In
          private BlogEntryDAO blogEntryDAO;
      
          @Begin
          public void addBlogEntry() {
              newBlogEntry = new BlogEntry();
              log.info("@Begin #0. Created and outjected a new blogEntry = #1.", this, newBlogEntry);
          }
      
          @End
          public void persist() {
              blogEntryDAO.persist(newBlogEntry);
              FacesMessages.instance().add("BlogEntry created.");
          }
      ...
      



      which is managed from this 2 pages:


      blogEntryList.xhtml:


      <s:link view="/xcms/blog/blogEntryCreate.xhtml" value="Create BlogEntry" action="#{blogEntryCreate.addBlogEntry()}"/>
      



      blogEntryCreate.xhtml:


      <h:form id="blogEntryForm">
                  <fieldset> 
                      <s:decorate id="bodyDecorate" template="/xcms/layout/edit.xhtml">
                          <ui:define name="label"> Body: </ui:define>
                          <h:inputTextarea id="body" rows="10" cols="17" value="#{blogEntryCreate.body}" required="true"> 
                              <a:support event="onblur" reRender="bodyDecorate"/>
                          </h:inputTextarea>
                      </s:decorate>
                      
                      <div class="buttonBox">
                          <s:link value="Ok" action="#{blogEntryCreate.persist()}" view="/xcms/blog/blogEntryList.xhtml"/>
                      </div>
                      
                  </fieldset>
              </h:form>
      



      The conversation starts as expected when entering blogEntryCreate.xhtml, but when trying to persist the newBlogEntry i got this exception:


      18:25:32,593 INFO  [BlogEntryDAO] BlogEntry.persist
      18:25:32,593 ERROR [SeamPhaseListener] uncaught exception
      javax.el.ELException: javax.ejb.EJBTransactionRolledbackException: no concurrent calls on stateful bean 'jboss.j2ee:service=EJB3,name=BlogEntryCreateBean' (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=BlogEntryCreateBean' (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 $Proxy790.persist(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_$$_javassist_5.persist(Object_$$_javassist_5.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=BlogEntryCreateBean' (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 $Proxy790.getBody(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_$$_javassist_5.getBody(Object_$$_javassist_5.java)
              at com.brit.xcms.blog.BlogEntryDAO.persist(BlogEntryDAO.java:35)
              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.transaction.TransactionInterceptor$1.work(TransactionInterceptor.java:38)
              at org.jboss.seam.util.Work.workInTransaction(Work.java:40)
              at org.jboss.seam.transaction.TransactionInterceptor.aroundInvoke(TransactionInterceptor.java:32)
              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.blog.BlogEntryDAO_$$_javassist_4.persist(BlogEntryDAO_$$_javassist_4.java)
              at com.brit.xcms.blog.BlogEntryCreateBean.persist(BlogEntryCreateBean.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.core.BijectionInterceptor.aroundInvoke(BijectionInterceptor.java:46)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              at org.jboss.seam.persistence.ManagedEntityIdentityInterceptor.aroundInvoke(ManagedEntityIdentityInterceptor.java:48)
              at org.jboss.seam.intercept.SeamInvocationContext.proceed(SeamInvocationContext.java:68)
              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.ConversationInterceptor.aroundInvoke(ConversationInterceptor.java:56)
              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.GeneratedMethodAccessor1441.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)
              ... 90 more
      
      



      I have found and read this form thread but the solution is not there. I am kind of new to Seam and i don't seam to understand why there are the 2 calls (addBlogEntry() and persist()) considered as concurrent when they are even called from different pages.


      Could anyone please post a hint on this?


      Thank you in advance,
      Bogdan.

        • 1. Re: ConcurrentAccessException: no concurrent calls on stateful bean
          Bogdan Minciu Newbie

          After analyzing the stack deeper, I have found the concurrent call:


          at com.brit.xcms.blog.BlogEntryCreateBean.persist(BlogEntryCreateBean.java:64)
          



          @Name("blogEntryDAO")
          @AutoCreate
          public class BlogEntryDAO {
          ...
              @In(create = true)
              private LocalBlogEntryView blogEntryView;
          
              @RaiseEvent("com.brit.xcms.blog.BlogEntry.blogEntriesListModified")
              public void persist(BlogEntry blogEntry) {
                  log.info("BlogEntry.persist");
                  blogEntry.setBody(blogEntryCreate.getBody());// <----- concurrent call here
                  entityManager.persist(blogEntry);
                  entityManager.flush();
              }
          ...
          }
          


          The workaround was to fill the newBlogEntry in my blogEntryCreate component and then pass it fully initialized to the DAO to be persisted.


          Anyway, the question now (for future problems) is: how can one component be accessed by multiple clients at the same time? Isn't the @Synchronized annotation made for this. As I read through its documentation it might/should be:




          Specifies that a stateful component has multiple concurrent clients, and so access to the component must be synchronized. This annotation is not required session scoped components, which are synchronized by default.


          My component is scoped to CONVERSATION, and not to SESSION so  I think I need it.

          • 2. Re: ConcurrentAccessException: no concurrent calls on stateful bean
            Bogdan Minciu Newbie

            TYPO:


            I introduced a TYPO in my last post, regarding the injected component in the DAO. The injected component was:


                @In(create = true)
                private LocalBlogEntryCreate blogEntryCreate;
            



            and not


                @In(create = true)
                private LocalBlogEntryView blogEntryView;
            



            I am sorry for the mistake; bad copy-paste.

            • 3. Re: ConcurrentAccessException: no concurrent calls on stateful bean
              John Lennon Newbie

              Hi,


              Did you found why bean annotated with @Stateful and @Synchronized is not allowing for concurrent access ?


              Regards,
              Adam.

              • 4. Re: ConcurrentAccessException: no concurrent calls on stateful bean
                John Lennon Newbie

                Hi,


                Did you found why there is concurent access exception event if '@Stateful' is annotated with '@Synchronized' ?


                Why should I add '@Synchronized' anyway if all calls to '@Stateful' are by default synchronised ?


                Regards,
                Adam.