1 2 Previous Next 16 Replies Latest reply on Jan 21, 2011 3:14 AM by Fin Steenbjerg

    stateful session beans and clustering

    Fin Steenbjerg Newbie

      I am testing the clustering features of JBoss AS 6.0 Final and I have a problem with stateful session bean (EJB) and clustering. I got a local stateful session bean which I want to use from a servlet and keep a reference to the session bean inside the http session. Ok the servlet looks up the stateful bean via JNDI and stores the returned proxy (the proxy returned from JNDI) into an attribute at the HttpSession. The next time the servlet is requested, it takes the proxy from the HttpSession and uses it. This works fine as long as the request doesn't switch server (another Jboss AS instance in the same cluster). If I switch node (due to a server crash) the servlet gets the proxy from the session (since session is replicated to between servers). But as soon as the servlet tries to use the proxy an exception is thrown (see below). It states that the object reference is not found. This makes since since the object reference was created at another server. But how can I overcome this problem. My question is "how do I use a stateful session beans from a shared object like a servlet and I want it to be session scoped"? Any comments are appreciated.

       

      14:33:06,000 ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[localhost].[/jb.tes.cluster.web].[dk.jyskebank.cluster.statefulsession.StatefulTestServlet]] Servlet.service() for servlet dk.jy

      skebank.cluster.statefulsession.StatefulTestServlet threw exception: javax.ejb.EJBException: java.lang.RuntimeException: java.io.IOException

              at org.jboss.ejb3.tx2.impl.CMTTxInterceptor.handleExceptionInOurTx(CMTTxInterceptor.java:183) [:0.0.1]

              at org.jboss.ejb3.tx2.impl.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:251) [:0.0.1]

              at org.jboss.ejb3.tx2.impl.CMTTxInterceptor.required(CMTTxInterceptor.java:349) [:0.0.1]

              at org.jboss.ejb3.tx2.impl.CMTTxInterceptor.invoke(CMTTxInterceptor.java:209) [:0.0.1]

              at org.jboss.ejb3.tx2.aop.CMTTxInterceptorWrapper.invoke(CMTTxInterceptorWrapper.java:52) [:0.0.1]

              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]

              at org.jboss.aspects.tx.TxPropagationInterceptor.invoke(TxPropagationInterceptor.java:76) [:1.0.0.GA]

              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]

              at org.jboss.aspects.remoting.ReplicantsManagerInterceptor.invoke(ReplicantsManagerInterceptor.java:56) [:1.0.1.GA]

              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]

              at org.jboss.ejb3.tx.NullInterceptor.invoke(NullInterceptor.java:42) [:1.0.3]

              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]

              at org.jboss.ejb3.security.Ejb3AuthenticationInterceptorv2.invoke(Ejb3AuthenticationInterceptorv2.java:182) [:1.7.17]

              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]

              at org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagationInterceptor.java:41) [:1.7.17]

              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]

              at org.jboss.ejb3.BlockContainerShutdownInterceptor.invoke(BlockContainerShutdownInterceptor.java:67) [:1.7.17]

              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]

              at org.jboss.ejb3.core.context.CurrentInvocationContextInterceptor.invoke(CurrentInvocationContextInterceptor.java:47) [:1.7.17]

              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]

              at org.jboss.aspects.currentinvocation.CurrentInvocationInterceptor.invoke(CurrentInvocationInterceptor.java:67) [:1.0.1]

              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]

              at org.jboss.ejb3.interceptor.EJB3TCCLInterceptor.invoke(EJB3TCCLInterceptor.java:86) [:1.7.17]

              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]

              at org.jboss.ejb3.session.SessionSpecContainer.invoke(SessionSpecContainer.java:323) [:1.7.17]

              at org.jboss.ejb3.session.SessionSpecContainer.invoke(SessionSpecContainer.java:380) [:1.7.17]

              at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [:1.6.0_23]

              at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) [:1.6.0_23]

              at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) [:1.6.0_23]

              at java.lang.reflect.Method.invoke(Method.java:597) [:1.6.0_23]

              at org.jboss.ejb3.proxy.impl.handler.session.SessionLocalProxyInvocationHandler$LocalContainerInvocation.invokeTarget(SessionLocalProxyInvocationHandler.java:184) [:1.0.11]

              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:111) [jboss-aop.jar:2.2.1.GA]

              at org.jboss.ejb3.async.impl.interceptor.AsynchronousClientInterceptor.invoke(AsynchronousClientInterceptor.java:143) [:1.7.17]

              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]

              at org.jboss.ejb3.proxy.impl.handler.session.SessionLocalProxyInvocationHandler$LocalInvokableContextHandler.invoke(SessionLocalProxyInvocationHandler.java:159) [:1.0.11]

              at $Proxy237.invoke(Unknown Source)     at org.jboss.ejb3.proxy.impl.handler.session.SessionProxyInvocationHandlerBase.invoke(SessionProxyInvocationHandlerBase.java:185) [:1.0.11]

              at $Proxy238.get(Unknown Source)        at dk.jyskebank.cluster.statefulsession.StatefulTestServlet.doGet(StatefulTestServlet.java:64) [:]

              at javax.servlet.http.HttpServlet.service(HttpServlet.java:734) [:1.0.0.Final]

              at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) [:1.0.0.Final]

              at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:324) [:6.0.0.Final]

              at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:242) [:6.0.0.Final]

              at org.jboss.weld.servlet.ConversationPropagationFilter.doFilter(ConversationPropagationFilter.java:67) [:6.0.0.Final]

              at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:274) [:6.0.0.Final]

              at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:242) [:6.0.0.Final]

              at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275) [:6.0.0.Final]

              at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191) [:6.0.0.Final]

              at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:181) [:6.0.0.Final]

              at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:593) [:6.0.0.Final]

              at org.jboss.web.tomcat.service.session.ClusteredSessionValve.handleRequest(ClusteredSessionValve.java:135) [:6.0.0.Final]

              at org.jboss.web.tomcat.service.session.ClusteredSessionValve.invoke(ClusteredSessionValve.java:94) [:6.0.0.Final]

              at org.jboss.web.tomcat.service.session.JvmRouteValve.invoke(JvmRouteValve.java:88) [:6.0.0.Final]

              at org.jboss.web.tomcat.service.session.LockingValve.invoke(LockingValve.java:62) [:6.0.0.Final]

              at org.jboss.modcluster.catalina.CatalinaContext$RequestListenerValve.event(CatalinaContext.java:285) [:1.1.0.Final]

              at org.jboss.modcluster.catalina.CatalinaContext$RequestListenerValve.invoke(CatalinaContext.java:261) [:1.1.0.Final]

              at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:88) [:6.0.0.Final]

              at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:100) [:6.0.0.Final]

              at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) [:6.0.0.Final]

              at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [:6.0.0.Final]

              at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158) [:6.0.0.Final]

              at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [:6.0.0.Final]

              at org.jboss.web.tomcat.service.request.ActiveRequestResponseCacheValve.invoke(ActiveRequestResponseCacheValve.java:53) [:6.0.0.Final]

              at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:362) [:6.0.0.Final]

              at org.apache.coyote.ajp.AjpProcessor.process(AjpProcessor.java:504) [:6.0.0.Final]

              at org.apache.coyote.ajp.AjpProtocol$AjpConnectionHandler.process(AjpProtocol.java:437) [:6.0.0.Final]

              at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:951) [:6.0.0.Final]

              at java.lang.Thread.run(Thread.java:662) [:1.6.0_23]

      Caused by: java.lang.RuntimeException: java.io.IOException

              at org.jboss.ejb3.stateful.StatefulBeanContext.extractBeanAndInterceptors(StatefulBeanContext.java:1011) [:1.7.17]

              at org.jboss.ejb3.stateful.StatefulBeanContext.postReplicate(StatefulBeanContext.java:689) [:1.7.17]

              at org.jboss.ejb3.cache.infinispan.InfinispanStatefulCache.get(InfinispanStatefulCache.java:409) [:1.0.0-alpha-4]

              at org.jboss.ejb3.stateful.StatefulInstanceAssociationInterceptor.invoke(StatefulInstanceAssociationInterceptor.java:50) [:1.7.17]

              at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102) [jboss-aop.jar:2.2.1.GA]

              at org.jboss.ejb3.core.context.SessionInvocationContextAdapter.proceed(SessionInvocationContextAdapter.java:95) [:1.7.17]

              at org.jboss.ejb3.tx2.impl.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:247) [:0.0.1]

              ... 66 more

      Caused by: java.io.IOException

              at org.jboss.serial.persister.RegularObjectPersister.readSlotWithMethod(RegularObjectPersister.java:107) [:6.0.0.Final]

              at org.jboss.serial.persister.RegularObjectPersister.defaultRead(RegularObjectPersister.java:269) [:6.0.0.Final]

              at org.jboss.serial.persister.RegularObjectPersister.readData(RegularObjectPersister.java:241) [:6.0.0.Final]

              at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.readObjectDescriptionFromStreaming(ObjectDescriptorFactory.java:412) [:6.0.0.Final]

              at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.objectFromDescription(ObjectDescriptorFactory.java:82) [:6.0.0.Final]

              at org.jboss.serial.objectmetamodel.DataContainer$DataContainerDirectInput.readObject(DataContainer.java:643) [:6.0.0.Final]

              at org.jboss.serial.persister.ArrayPersister.readObjectArray(ArrayPersister.java:196) [:6.0.0.Final]

              at org.jboss.serial.persister.ArrayPersister.readData(ArrayPersister.java:172) [:6.0.0.Final]

              at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.readObjectDescriptionFromStreaming(ObjectDescriptorFactory.java:412) [:6.0.0.Final]

              at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.objectFromDescription(ObjectDescriptorFactory.java:82) [:6.0.0.Final]

              at org.jboss.serial.objectmetamodel.DataContainer$DataContainerDirectInput.readObject(DataContainer.java:643) [:6.0.0.Final]

              at org.jboss.serial.io.JBossObjectInputStream.readObjectOverride(JBossObjectInputStream.java:163) [:6.0.0.Final]

              at java.io.ObjectInputStream.readObject(ObjectInputStream.java:344) [:1.6.0_23]

              at org.jboss.serial.io.MarshalledObject.get(MarshalledObject.java:68) [:6.0.0.Final]

              at org.jboss.ejb3.stateful.StatefulBeanContext.extractBeanAndInterceptors(StatefulBeanContext.java:982) [:1.7.17]

              ... 72 more

      Caused by: java.lang.reflect.InvocationTargetException

              at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [:1.6.0_23]

              at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) [:1.6.0_23]

              at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) [:1.6.0_23]

              at java.lang.reflect.Method.invoke(Method.java:597) [:1.6.0_23]

              at org.jboss.serial.persister.RegularObjectPersister.readSlotWithMethod(RegularObjectPersister.java:103) [:6.0.0.Final]

              ... 86 more

      Caused by: org.jboss.serial.exception.SerializationException: Object reference 9 was not found

              at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.objectFromDescription(ObjectDescriptorFactory.java:118) [:6.0.0.Final]

              at org.jboss.serial.objectmetamodel.DataContainer$DataContainerDirectInput.readObject(DataContainer.java:643) [:6.0.0.Final]

              at org.jboss.serial.persister.RegularObjectPersister.readSlotWithFields(RegularObjectPersister.java:353) [:6.0.0.Final]

              at org.jboss.serial.persister.RegularObjectPersister.defaultRead(RegularObjectPersister.java:273) [:6.0.0.Final]

              at org.jboss.serial.persister.RegularObjectPersister.readData(RegularObjectPersister.java:241) [:6.0.0.Final]

              at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.readObjectDescriptionFromStreaming(ObjectDescriptorFactory.java:412) [:6.0.0.Final]

              at org.jboss.serial.objectmetamodel.ObjectDescriptorFactory.objectFromDescription(ObjectDescriptorFactory.java:82) [:6.0.0.Final]

              at org.jboss.serial.objectmetamodel.DataContainer$DataContainerDirectInput.readObject(DataContainer.java:643) [:6.0.0.Final]

              at org.jboss.serial.persister.ObjectInputStreamProxy.readObjectOverride(ObjectInputStreamProxy.java:68) [:6.0.0.Final]

              at java.io.ObjectInputStream.readObject(ObjectInputStream.java:344) [:1.6.0_23]

              at java.util.ArrayList.readObject(ArrayList.java:593) [:1.6.0_23]

              ... 91 more

       

      The session bean looks like this:

       

       

       

      @Local

      public interface StatefulTest extends Serializable {

          int get();

          @Remove

          void reset();

          @Init

          void initialize(int value);

      }

       

      @Stateful

      @Clustered()

      public class StatefulTestBean implements Serializable, StatefulTest {

          private static Logger logger = LoggerFactory.getLogger(StatefulTestBean.class);

       

          private int balance = 0;

       

          public StatefulTestBean() {

          }

       

          @Init

          @Override

          public void initialize(int value) {

              balance = value;

          }

       

          @Override

          public int get() {

              return balance;

          }

       

          @Override

          @Remove

          public void reset() {

              logger.info("reset");

          }

      }

       

       

      The servlet looks like this:

       

      @WebServlet("/stateful")

      @ServletSecurity(@HttpConstraint(rolesAllowed = {"jbwindowsusers"}))

      @DeclareRoles("jbwindowsusers")

      public class StatefulTestServlet extends HttpServlet {

          private static final String STATEFULTEST_JNDI_PATH = "jb.tes.cluster/StatefulTestBean/local";

          private static final String SESSION_ATTRIBUTE_NAME = "statefultest";

          private static final Logger logger = LoggerFactory.getLogger(StatefulTestBean.class);

          private static final SimpleDateFormat dateFormat = new SimpleDateFormat("EEE, d MMM yyyy HH:mm:ss");

       

          public StatefulTestServlet() {

          }

       

          @Override

          protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException {

              String action = request.getParameter("action");

              PrintWriter out = null;

              try {

                  out = response.getWriter();

                  out.println("Invoked at '" + System.getProperty("jboss.jvmRoute") + "' by user '" + request.getUserPrincipal().getName() + "' with session id '" + request.getSession().getId() + "' at '" + dateFormat.format(new Date()) + "'");

       

                  StatefulTest bean = getBean(request.getSession());

       

                  if ("init".equalsIgnoreCase(action)) {

                      String initData = request.getParameter("data");

                      int initializationValue = 17;

                      try {

                          initializationValue = Integer.parseInt(initData);

                      } catch(NumberFormatException e) {                   

                      }

                      bean.initialize(initializationValue);

                      out.println("Initialize to : '" + initializationValue + "' for " + bean);

                  } else if ("remove".equalsIgnoreCase(action)) {

                      request.getSession().invalidate();

                      out.println("session has been invalidated");

                  } else { // get action is the default action

                      out.println("balance : '" + bean.get() + "'");

                  }

              } catch (IOException e) {

                  throw new ServletException("failed to get an output stream", e);

              } finally {

                  if (out != null) {

                      out.close();

                  }

              }       

          }

       

          private StatefulTest getBean(HttpSession session) {

              try {

                  StatefulTest bean = (StatefulTest) session.getAttribute(SESSION_ATTRIBUTE_NAME);

                  if (bean == null) {

                      // lookup bean in JNDI

                      InitialContext ic = new InitialContext();

                      bean = (StatefulTest) ic.lookup(STATEFULTEST_JNDI_PATH);

                      logger.info("Found bean '" + bean + "' of type '" + bean.getClass().getName() + "'");

       

                      // add to session

                      session.setAttribute(SESSION_ATTRIBUTE_NAME, bean);

                  }

                  return bean;

              } catch (NamingException e) {

                  throw new RuntimeException("Failed to retrieve stateful session bean", e);

              }

          }

       

        • 1. stateful session beans and clustering
          Fin Steenbjerg Newbie

          Is there nobody who knows how I can use a stateful session bean from a servlet when I want it to be session dependent and the session needs to be distributed across servers (cluster aware)?

          • 2. stateful session beans and clustering
            Nicklas Karlsson Master

            I think resource injection (@EJB) is not a good idea but you could look it up in JNDI and stick the reference in the http session and that might lead to automagical clustering (must say I'm not sure about it). You might also want to investigate if @Inject circumvents the "stateful injection into stateless object" problem.

            • 3. Re: stateful session beans and clustering
              Fin Steenbjerg Newbie

              First I tried @EJB and that certainly does work due to how the servlet model works. The above sample code actually looks it up in JNDI and stick the proxy into the session. That works on a single node but fails with the above exception when changing servers (due to a server crash). I dont think @Inject or will work since the servlet object are shared for servlets. Any other idea that I could try out ?

              • 4. stateful session beans and clustering
                Nicklas Karlsson Master

                Without trying it, I would have guessed @Inject to work because there's a proxy injected and the session context is a HttpSession-backed ThreadLocal construct...

                • 5. stateful session beans and clustering
                  Paul Ferraro Master

                  Have you tried changing your @Clustered SFSB to use @Remote?

                  • 6. stateful session beans and clustering
                    Fin Steenbjerg Newbie

                    yes I have tried to change it to a remote. Same thing unfortunately.

                     

                    Nicklas, I will try the @inject as soon as I am back to my computer.

                    • 7. Re: stateful session beans and clustering
                      Fin Steenbjerg Newbie

                      @inject inside a servlet works. That's great.

                       

                      But it only works as long I am running at a single jboss server and don't get into a fail over situation. In case, the node at which the requests has been handled crashes the request are forwarded to another jboss node, but at this node the session can't not be accessed. A warning is written to the log:

                       

                       

                      14:39:05,505WARN [org.jboss.web.tomcat.service.session.distributedcache.ispn.DistributedCacheManager]Problem accessing session [FT****SUUA__]: java.lang.NullPointerException

                       

                      and the session attributes are dropped.

                       

                      • 8. Re: stateful session beans and clustering
                        Paul Ferraro Master

                        Can you attach the full NPE trace?

                        • 9. Re: stateful session beans and clustering
                          Fin Steenbjerg Newbie

                          I am sorry but there is only the warning, no stacktrace.

                          • 10. Re: stateful session beans and clustering
                            Paul Ferraro Master

                            If you lower your logging threshold for org.jboss.web.tomcat.service.session.distributedcache.ispn.DistributedCacheManager to DEBUG, you should see the stacktrace.

                            • 11. stateful session beans and clustering
                              Fin Steenbjerg Newbie

                              Nice. Here is the stacktrace:

                               

                              2011-01-18 22:02:13,176 WARN  [org.jboss.web.tomcat.service.session.distributedcache.ispn.DistributedCacheManager] (ajp-127.0.0.1-8209-1) Problem accessing session [MG****SLVw__]: java.lang.NullPointerException

                              2011-01-18 22:02:13,176 DEBUG [org.jboss.web.tomcat.service.session.distributedcache.ispn.DistributedCacheManager] (ajp-127.0.0.1-8209-1) Problem accessing session [MG****SLVw__]: java.lang.NullPointerException: java.lang.NullPointerException

                                  at org.jboss.weld.bean.proxy.ProxyFactory.resolveClassLoaderForBeanProxy(ProxyFactory.java:990) [:6.0.0.Final]

                                  at org.jboss.weld.bean.proxy.util.SerializableProxy.readObject(SerializableProxy.java:115) [:6.0.0.Final]

                                  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [:1.6.0_23]

                                  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) [:1.6.0_23]

                                  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) [:1.6.0_23]

                                  at java.lang.reflect.Method.invoke(Method.java:597) [:1.6.0_23]

                                  at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:974) [:1.6.0_23]

                                  at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1848) [:1.6.0_23]

                                  at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752) [:1.6.0_23]

                                  at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328) [:1.6.0_23]

                                  at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1946) [:1.6.0_23]

                                  at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1870) [:1.6.0_23]

                                  at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752) [:1.6.0_23]

                                  at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328) [:1.6.0_23]

                                  at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350) [:1.6.0_23]

                                  at java.util.HashMap.readObject(HashMap.java:1030) [:1.6.0_23]

                                  at sun.reflect.GeneratedMethodAccessor294.invoke(Unknown Source) [:1.6.0_23]

                                  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) [:1.6.0_23]

                                  at java.lang.reflect.Method.invoke(Method.java:597) [:1.6.0_23]

                                  at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:974) [:1.6.0_23]

                                  at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1848) [:1.6.0_23]

                                  at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752) [:1.6.0_23]

                                  at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328) [:1.6.0_23]

                                  at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350) [:1.6.0_23]

                                  at org.jboss.ha.framework.server.SimpleCachableMarshalledValue.get(SimpleCachableMarshalledValue.java:165) [:2.0.0.Final]

                                  at org.jboss.web.tomcat.service.session.distributedcache.impl.SessionAttributeMarshallerImpl.unmarshal(SessionAttributeMarshallerImpl.java:89) [:3.0.0.Final]

                                  at org.jboss.web.tomcat.service.session.distributedcache.ispn.CoarseSessionAttributeStorage.load(CoarseSessionAttributeStorage.java:66) [:1.0.0.Final]

                                  at org.jboss.web.tomcat.service.session.distributedcache.ispn.DistributedCacheManager$2.invoke(DistributedCacheManager.java:270) [:1.0.0.Final]

                                  at org.jboss.web.tomcat.service.session.distributedcache.ispn.DistributedCacheManager$2.invoke(DistributedCacheManager.java:252) [:1.0.0.Final]

                                  at org.jboss.ha.ispn.invoker.RetryingCacheInvoker.invoke(RetryingCacheInvoker.java:69) [:1.0.0.Final]

                                  at org.jboss.web.tomcat.service.session.distributedcache.ispn.DistributedCacheManager.getData(DistributedCacheManager.java:284) [:1.0.0.Final]

                                  at org.jboss.web.tomcat.service.session.distributedcache.ispn.DistributedCacheManager.getSessionData(DistributedCacheManager.java:234) [:1.0.0.Final]

                                  at org.jboss.web.tomcat.service.session.JBossCacheManager.loadSession(JBossCacheManager.java:2209) [:6.0.0.Final]

                                  at org.jboss.web.tomcat.service.session.JBossCacheManager.findSession(JBossCacheManager.java:626) [:6.0.0.Final]

                                  at org.apache.catalina.connector.Request.doGetSession(Request.java:2558) [:6.0.0.Final]

                                  at org.apache.catalina.connector.Request.getSession(Request.java:2315) [:6.0.0.Final]

                                  at org.jboss.web.tomcat.service.session.JvmRouteValve.checkJvmRoute(JvmRouteValve.java:95) [:6.0.0.Final]

                                  at org.jboss.web.tomcat.service.session.JvmRouteValve.invoke(JvmRouteValve.java:85) [:6.0.0.Final]

                                  at org.jboss.web.tomcat.service.session.LockingValve.invoke(LockingValve.java:62) [:6.0.0.Final]

                                  at org.jboss.modcluster.catalina.CatalinaContext$RequestListenerValve.event(CatalinaContext.java:285) [:1.1.0.Final]

                                  at org.jboss.modcluster.catalina.CatalinaContext$RequestListenerValve.invoke(CatalinaContext.java:261) [:1.1.0.Final]

                                  at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:88) [:6.0.0.Final]

                                  at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:100) [:6.0.0.Final]

                                  at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127) [:6.0.0.Final]

                                  at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [:6.0.0.Final]

                                  at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158) [:6.0.0.Final]

                                  at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [:6.0.0.Final]

                                  at org.jboss.web.tomcat.service.request.ActiveRequestResponseCacheValve.invoke(ActiveRequestResponseCacheValve.java:53) [:6.0.0.Final]

                                  at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:362) [:6.0.0.Final]

                                  at org.apache.coyote.ajp.AjpProcessor.process(AjpProcessor.java:504) [:6.0.0.Final]

                                  at org.apache.coyote.ajp.AjpProtocol$AjpConnectionHandler.process(AjpProtocol.java:437) [:6.0.0.Final]

                                  at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:951) [:6.0.0.Final]

                                  at java.lang.Thread.run(Thread.java:662) [:1.6.0_23]

                              • 12. stateful session beans and clustering
                                Thunder Lei Newbie

                                Just a guess on this issue.

                                 

                                The problem maybe that crashed server  is the very node that clustered EJB proxy is currently connecting to.

                                I have this guess base on my understanding about the "Client-side interceptor architecture" and my test on clustered EJB, pls see

                                http://community.jboss.org/thread/161054

                                 

                                I think of a test-case that can verify my assumption.

                                1. create a three nodes cluster with node A, B and C.

                                2. deploy the clustered EJB on B and C Only.

                                3. request the servlet from A, then shutdown A

                                4. request the servlet from server B

                                5. if the clustered EJB works fine, then it demonstrates my assumption.

                                 

                                Recently I am pretty busy on development work and plan to carry on this test latter.

                                anyone who thinks my assumption is reasonable can perform the test.

                                And if anyone have valid point that can negate my assuption, pls share it with us.

                                 

                                Thunder

                                • 13. Re: stateful session beans and clustering
                                  Thunder Lei Newbie
                                  I am testing the clustering features of JBoss AS 6.0 Final and I have a problem with stateful session bean (EJB) and clustering. I got a local stateful session bean which I want to use from a servlet and keep a reference to the session bean inside the http session. Ok the servlet looks up the stateful bean via JNDI and stores the returned proxy (the proxy returned from JNDI) into an attribute at the HttpSession. The next time the servlet is requested, it takes the proxy from the HttpSession and uses it. This works fine as long as the request doesn't switch server (another Jboss AS instance in the same cluster). If I switch node (due to a server crash) the servlet gets the proxy from the session (since session is replicated to between servers). But as soon as the servlet tries to use the proxy an exception is thrown (see below). It states that the object reference is not found. This makes since since the object reference was created at another server. But how can I overcome this problem. My question is "how do I use a stateful session beans from a shared object like a servlet and I want it to be session scoped"? Any comments are appreciated.

                                  Also another simple alternative test that can verify my above guess:

                                  You can just request the serverlet to another node, and don't shutdown any server. If the clustered EJB works fine, that can prove my guess to be true.

                                   

                                  Thunder

                                  • 14. Re: stateful session beans and clustering
                                    Fin Steenbjerg Newbie

                                    Hi Thunder Lei. I guess what you are  taking about here is clustering of remote EJBs and looking up proxies via HA-JNDI. My case, is not quite that. My stateful ejb is a local bean accessed from a servlet within the same application via normal JNDI or via simple injection. The clustering in this case comes down to session replication of the bean state. Later on, I have to test HA-JNDI for access service made available via remote EJBs. If I am not correct please correct me.

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