Invoking session Bean second time gives me error

[Shah, Ritesh]

Hi, 
  I am getting the following error when I am invoking my session bean second
time. First time it works perfectly and second time it gives the following
error.

  How can I solve this error. Any help will be appreciated.
Thanks
Ritesh.


My Code:

        private IntialContex getInitialContext(String app)
        {
                String appUrl= "ormi://localhost:8888/";
                appUrl= appUrl + app;
                java.util.Hashtable tab= new java.util.Hashtable();
                tab.put("java.naming.factory.initial",
"com.evermind.server.ApplicationClientInitialContextFactory");
                tab.put("java.naming.provider.url", appUrl);
                tab.put("java.naming.security.principal", "admin");
                tab.put("java.naming.security.credentials", "password");
                return new javax.naming.InitialContext(tab);
        }



// in servlet

        InitialContext ictx= getInitialContext(apps);
        userManagerHome= (UserManagerHome)
PortableRemoteObject.narrow(ictx.lookup("java:comp/env/UserManager"),
UserManagerHome.class);
        UserManager userM = userMangerHome.create();    
        userM.doLogin(userName,Password);



//application Client file

        <ejb-ref>
                <ejb-ref-name>UserManager</ejb-ref-name>
                <ejb-ref-type>Session</ejb-ref-type>
                <home>com.aclcargo.sessionbean.UserManagerHome</home>
                <remote>com.aclcargo.sessionbean.UserManager</remote>
        </ejb-ref>


//Error on second Request


com.evermind[Oracle9iAS (1.0.2.2) Containers for
J2EE].server.rmi.OrionRemoteException: java.lang.NullPointerException

        at com.evermind[Oracle9iAS (1.0.2.2) Containers for
J2EE].server.ejb.EJBUtils.getUserException(EJBUtils.java:199)

        at
UserManager_StatelessSessionBeanWrapper0.doLogin(UserManager_StatelessSessio
nBeanWrapper0.java:64)

        at Login.service(ActionMultiplexer.java:73)

        at javax.servlet.http.HttpServlet.service(HttpServlet.java:336)

        at com.evermind[Oracle9iAS (1.0.2.2) Containers for
J2EE].server.http.ServletRequestDispatcher.invoke(ServletRequestDispatcher.j
ava:501)

        at com.evermind[Oracle9iAS (1.0.2.2) Containers for
J2EE].server.http.ServletRequestDispatcher.forwardInternal(ServletRequestDis
patcher.java:170)

        at com.evermind[Oracle9iAS (1.0.2.2) Containers for
J2EE].server.http.HttpRequestHandler.processRequest(HttpRequestHandler.java:
576)

        at com.evermind[Oracle9iAS (1.0.2.2) Containers for
J2EE].server.http.HttpRequestHandler.run(HttpRequestHandler.java:189)

        at com.evermind[Oracle9iAS (1.0.2.2) Containers for
J2EE].util.ThreadPoolThread.run(ThreadPoolThread.java:62)


        Nested exception is:

java.lang.NullPointerException

        at
com.aclcargo.sessionbean.BeansHome.getRegisteredUserHome(BeansHome.java:58)

        at
com.aclcargo.sessionbean.UserManagerBean.doLogin(UserManagerBean.java:45)

        at
UserManager_StatelessSessionBeanWrapper0.doLogin(UserManager_StatelessSessio
nBeanWrapper0.java:54)

        at Login.service(ActionMultiplexer.java:73)

        at javax.servlet.http.HttpServlet.service(HttpServlet.java:336)

        at com.evermind[Oracle9iAS (1.0.2.2) Containers for
J2EE].server.http.ServletRequestDispatcher.invoke(ServletRequestDispatcher.j
ava:501)

        at com.evermind[Oracle9iAS (1.0.2.2) Containers for
J2EE].server.http.ServletRequestDispatcher.forwardInternal(ServletRequestDis
patcher.java:170)

        at com.evermind[Oracle9iAS (1.0.2.2) Containers for
J2EE].server.http.HttpRequestHandler.processRequest(HttpRequestHandler.java:
576)

        at com.evermind[Oracle9iAS (1.0.2.2) Containers for
J2EE].server.http.HttpRequestHandler.run(HttpRequestHandler.java:189)

        at com.evermind[Oracle9iAS (1.0.2.2) Containers for
J2EE].util.ThreadPoolThread.run(ThreadPoolThread.java:62)