PortableRemoteObject.narrow(...) error , why?

when I execute
PortableRemoteObject.narrow(objred, SBeanHome.class);
the system throw an exception
java.lang.ClassCastException: $Proxy78
Please help me!
(my application server is weblogic 6.1)

Object obj = (MyHomeInterface) ctx.lookup("Invoice.MyHomeInterface");
MyHomeInterface home = (MyHomeInterface) PortableRemoteObject.narrow(obj, MyHomeInterface.class);
use this code instead.
i hope that this will solve your problem change the code according to your classes.

Similar Messages

Why PortableRemoteObject.narrow()

Hello,
Can any one please suggest me the difference in looking Up of the components in 2 ways..??
1) HelloHome home = (HelloHome)ctx.lookup("HelloHome")
2) Object ref = getInitialContext().lookup(eb/HelloBean);
HelloHome home = (HelloHome)javax.rmi.PortableRemoteObject.narrow(ref, HelloHome.class)
Why we need option 2 when we get a home object when we make a look up as in 1.
why PortableRemoteObject.narrow()
Please make ur suggestions.
Thanks.

Hi,
From an article at http://java.sun.com/blueprints/guidelines/designing_enterprise_applications_2e/ejb-tier/ejb-tier9.html
Type narrowing is needed because many application servers use RMI-IIOP as the communication protocol to access remote beans. However, some application servers do not use RMI-IIOP and hence allow the use of Java language typecasts as well. For portability you cannot rely on an application server allowing Java language typecasts; you should always use the PortableRemoteObject.narrow method. The overhead on this method call is usually quite small
-Amol

A error from javax.rmi.PortableRemoteObject.narrow

--run envrionment: jdk1.4.2_01 / oc4j9.0.4
--source code
import java.util.*;
import java.io.IOException;
import java.rmi.RemoteException;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.ejb.*;
import javax.naming.*;
import javax.rmi.PortableRemoteObject;
import java.sql.*;
public class ProductServlet extends HttpServlet
server.ProductHome myProductHome;
public void init() throws ServletException {
try {
Hashtable env = new Hashtable();
env.put(Context.INITIAL_CONTEXT_FACTORY,
"com.evermind.server.rmi.RMIInitialContextFactory");
env.put(Context.PROVIDER_URL, "ormi://localhost/JDBCEJB");
env.put(Context.SECURITY_PRINCIPAL, "store_user");
env.put(Context.SECURITY_CREDENTIALS, "store_password");
Context myInitialContext = new InitialContext(env);
Object homeObject = myInitialContext.lookup("ProductBean");
myProductHome = (server.ProductHome)PortableRemoteObject.narrow(homeObject,server.ProductHome.class);
} catch(NamingException e) {
throw new ServletException("Error looking up home", e);
public void doGet(
HttpServletRequest request, HttpServletResponse response
) throws ServletException, IOException {
response.setContentType("text/html;charset=BIG5");
ServletOutputStream out = response.getOutputStream();
out.println("<html>");
out.println("<head><title>Product</title></head>");
out.println("<body>");
out.println("<table width=100% border=1>");
out.println("<tr>");
out.println("<th>Id</th>");
out.println("<th>Name</th>");
out.println("<th>Address</th>");
out.println("<th>Bdate</th>");
out.println("</tr>");
try {
server.ProductRemote myProductRemote = myProductHome.create();
server.Product myProduct = myProductRemote.query(request.getParameter("guess"));
if (myProduct != null) {
out.println("<tr>");
out.println("<td>" + myProduct.id + "</td>");
out.println("<td>" + myProduct.name + "</td>");
out.println("<td>" + myProduct.ads + "</td>");
out.println("<td>" + myProduct.bdate + "</td>");
out.println("</tr>");
out.println("</table>");
out.println("</body></html>");
} catch(RemoteException e) {
out.println("Error communicating with EJB-server: " +
e.getMessage());
} catch(CreateException e) {
out.println("Error creating EJB: " + e.getMessage());
} catch(SQLException e) {
out.println("SQL Exception: " + e.getMessage());
--My application client can run correctly, but my servlet code can't run.
--If I start oc4j by follow statement:
java -jar oc4j.jar
--the error display:
java.lang.ClassCastException
     at com.sun.corba.se.internal.javax.rmi.PortableRemoteObject.narrow(PortableRemoteObject.java:293)
     at javax.rmi.PortableRemoteObject.narrow(PortableRemoteObject.java:134)
     at ProductServlet.init(ProductServlet.java:39)
     at javax.servlet.GenericServlet.init(GenericServlet.java:258)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpApplication.loadServlet(HttpApplication.java:2091)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpApplication.findServlet(HttpApplication.java:4507)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpApplication.getRequestDispatcher(HttpApplication.java:2410)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpRequestHandler.processRequest(HttpRequestHandler.java:629)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpRequestHandler.run(HttpRequestHandler.java:264)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpRequestHandler.run(HttpRequestHandler.java:107)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].util.ReleasableResourcePooledExecutor$MyWorker.run(ReleasableResourcePooledExecutor.java:186)
     at java.lang.Thread.run(Thread.java:534)
--If I start oc4j by follow statement:
java -jar -Djavax.rmi.CORBA.PortableRemoteObjectClass=com.sun.corba.se.internal.javax.rmi.PortableRemoteObject -Djavax.rmi.CORBA.UtilClass=com.sum.corba.se.internal.POA.ShutdownUtilDelegate oc4j.jar
--the error is:
java.lang.ExceptionInInitializerError
     at javax.rmi.PortableRemoteObject.createDelegateIfSpecified(PortableRemoteObject.java:179)
     at javax.rmi.PortableRemoteObject.<clinit>(PortableRemoteObject.java:58)
     at ProductServlet.init(ProductServlet.java:39)
     at javax.servlet.GenericServlet.init(GenericServlet.java:258)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpApplication.loadServlet(HttpApplication.java:2091)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpApplication.findServlet(HttpApplication.java:4507)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpApplication.getRequestDispatcher(HttpApplication.java:2410)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpRequestHandler.processRequest(HttpRequestHandler.java:629)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpRequestHandler.run(HttpRequestHandler.java:264)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpRequestHandler.run(HttpRequestHandler.java:107)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].util.ReleasableResourcePooledExecutor$MyWorker.run(ReleasableResourcePooledExecutor.java:186)
     at java.lang.Thread.run(Thread.java:534)
Caused by: org.omg.CORBA.INITIALIZE: cannot instantiate com.sum.corba.se.internal.POA.ShutdownUtilDelegate vmcid: 0x0 minor code: 0 completed: No
     at javax.rmi.CORBA.Util.createDelegateIfSpecified(Util.java:341)
     at javax.rmi.CORBA.Util.<clinit>(Util.java:51)
     ... 12 more

--run envrionment: jdk1.4.2_01 / oc4j9.0.4
--source code
import java.util.*;
import java.io.IOException;
import java.rmi.RemoteException;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.ejb.*;
import javax.naming.*;
import javax.rmi.PortableRemoteObject;
import java.sql.*;
public class ProductServlet extends HttpServlet
server.ProductHome myProductHome;
public void init() throws ServletException {
try {
Hashtable env = new Hashtable();
env.put(Context.INITIAL_CONTEXT_FACTORY,
"com.evermind.server.rmi.RMIInitialContextFactory");
env.put(Context.PROVIDER_URL, "ormi://localhost/JDBCEJB");
env.put(Context.SECURITY_PRINCIPAL, "store_user");
env.put(Context.SECURITY_CREDENTIALS, "store_password");
Context myInitialContext = new InitialContext(env);
Object homeObject = myInitialContext.lookup("ProductBean");
myProductHome = (server.ProductHome)PortableRemoteObject.narrow(homeObject,server.ProductHome.class);
} catch(NamingException e) {
throw new ServletException("Error looking up home", e);
public void doGet(
HttpServletRequest request, HttpServletResponse response
) throws ServletException, IOException {
response.setContentType("text/html;charset=BIG5");
ServletOutputStream out = response.getOutputStream();
out.println("<html>");
out.println("<head><title>Product</title></head>");
out.println("<body>");
out.println("<table width=100% border=1>");
out.println("<tr>");
out.println("<th>Id</th>");
out.println("<th>Name</th>");
out.println("<th>Address</th>");
out.println("<th>Bdate</th>");
out.println("</tr>");
try {
server.ProductRemote myProductRemote = myProductHome.create();
server.Product myProduct = myProductRemote.query(request.getParameter("guess"));
if (myProduct != null) {
out.println("<tr>");
out.println("<td>" + myProduct.id + "</td>");
out.println("<td>" + myProduct.name + "</td>");
out.println("<td>" + myProduct.ads + "</td>");
out.println("<td>" + myProduct.bdate + "</td>");
out.println("</tr>");
out.println("</table>");
out.println("</body></html>");
} catch(RemoteException e) {
out.println("Error communicating with EJB-server: " +
e.getMessage());
} catch(CreateException e) {
out.println("Error creating EJB: " + e.getMessage());
} catch(SQLException e) {
out.println("SQL Exception: " + e.getMessage());
--My application client can run correctly, but my servlet code can't run.
--If I start oc4j by follow statement:
java -jar oc4j.jar
--the error display:
java.lang.ClassCastException
     at com.sun.corba.se.internal.javax.rmi.PortableRemoteObject.narrow(PortableRemoteObject.java:293)
     at javax.rmi.PortableRemoteObject.narrow(PortableRemoteObject.java:134)
     at ProductServlet.init(ProductServlet.java:39)
     at javax.servlet.GenericServlet.init(GenericServlet.java:258)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpApplication.loadServlet(HttpApplication.java:2091)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpApplication.findServlet(HttpApplication.java:4507)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpApplication.getRequestDispatcher(HttpApplication.java:2410)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpRequestHandler.processRequest(HttpRequestHandler.java:629)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpRequestHandler.run(HttpRequestHandler.java:264)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpRequestHandler.run(HttpRequestHandler.java:107)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].util.ReleasableResourcePooledExecutor$MyWorker.run(ReleasableResourcePooledExecutor.java:186)
     at java.lang.Thread.run(Thread.java:534)
--If I start oc4j by follow statement:
java -jar -Djavax.rmi.CORBA.PortableRemoteObjectClass=com.sun.corba.se.internal.javax.rmi.PortableRemoteObject -Djavax.rmi.CORBA.UtilClass=com.sum.corba.se.internal.POA.ShutdownUtilDelegate oc4j.jar
--the error is:
java.lang.ExceptionInInitializerError
     at javax.rmi.PortableRemoteObject.createDelegateIfSpecified(PortableRemoteObject.java:179)
     at javax.rmi.PortableRemoteObject.<clinit>(PortableRemoteObject.java:58)
     at ProductServlet.init(ProductServlet.java:39)
     at javax.servlet.GenericServlet.init(GenericServlet.java:258)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpApplication.loadServlet(HttpApplication.java:2091)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpApplication.findServlet(HttpApplication.java:4507)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpApplication.getRequestDispatcher(HttpApplication.java:2410)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpRequestHandler.processRequest(HttpRequestHandler.java:629)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpRequestHandler.run(HttpRequestHandler.java:264)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].server.http.HttpRequestHandler.run(HttpRequestHandler.java:107)
     at com.evermind[Oracle9iAS (9.0.4.0.0) Containers for J2EE].util.ReleasableResourcePooledExecutor$MyWorker.run(ReleasableResourcePooledExecutor.java:186)
     at java.lang.Thread.run(Thread.java:534)
Caused by: org.omg.CORBA.INITIALIZE: cannot instantiate com.sum.corba.se.internal.POA.ShutdownUtilDelegate vmcid: 0x0 minor code: 0 completed: No
     at javax.rmi.CORBA.Util.createDelegateIfSpecified(Util.java:341)
     at javax.rmi.CORBA.Util.<clinit>(Util.java:51)
     ... 12 more

[b]Periodic[/b] error using PortableRemoteObject.narrow

I am trying to access a session bean on an oracle9ias(903) running on a windows 2000 server.
Well I am actually accessing several beans, but on some of the beans the code works and on some it don't even though the code is alike. There is no execptions thrown but the LabelTypeDAOHome is null and I get a NPE when calling create on it.
public static Context getInitialContext() throws NamingException, MissingResourceException
Hashtable env = new Hashtable();
String init = getResourceBundle().getString("INITIAL_CONTEXT_FACTORY");
env.put(Context.INITIAL_CONTEXT_FACTORY,init);
String principle = getResourceBundle().getString("SECURITY_PRINCIPAL");
env.put(Context.SECURITY_PRINCIPAL,principle);
String credential = getResourceBundle().getString("SECURITY_CREDENTIALS");
env.put(Context.SECURITY_CREDENTIALS,credential);
String url = getResourceBundle().getString("PROVIDER_URL");
env.put(Context.PROVIDER_URL,url);
env.put("dedicated.rmicontext","true"); // vigtig ifm web access!
return new InitialContext(env);
private LabelTypeDAO getLabeltypeDAO() throws NamingException, RemoteException {
LabelTypeDAO labeltypeDAO = null;
if (context == null) {
context = getInitialContext();
if (labeltypeDAOHome == null) {
LabelTypeDAOHome labeltypeDAOHome = (LabelTypeDAOHome)PortableRemoteObject.narrow(context.lookup("LabelTypeDAO"), LabelTypeDAOHome.class);
try {
labeltypeDAO = labeltypeDAOHome.create();
} catch(Exception ce) {
throw new RemoteException("Could not create LabelTypeDAO.", ce);
return labeltypeDAO;
The funny part is that it doesn't happen on all the sessionbeans.
Could it have something to do with what happens on deployment (e.g internal wrapping).
There is no exception thrown untill I call labeltypeDAO = labeltypeDAOHome.create();
This code is in a java class instantiated in a jsp page.

Found it. It was my own stupid mistake. I had 2 references to the same variable name, one to an instance variable and one to a local variable and I ofcourse referenced the wrong one.
Bad lars
Bad lars
Bad lars

PortableRemoteObject.narrow

Why is it necessary to use and cast the result of this method call, which appears to return the same object as was passed as the first argument? In other words, why do this:
Object myObj = ctx.lookup(MYHOME);
MyHome myHome = (MyHome)
PortableRemoteObject.narrow(myObj, MyHome.class);
MyEjb myEjb = myHome.create();
-in code that must know each EJB, when you can do this:
//In a generic HomeFactory class
Object myObj = ctx.lookup(MYHOME);
Class beanHome = Class.forName(MYHOME);
PortableRemoteObject.narrow(myObj, beanHome);
return myObj
//In some other class
MyHome myHome = (MyHome) HomeFactory.getHome(MYHOME);
MyEjb = myHome.create();
I left out the try-catch blocks and all of that for compactness. The reason I ask is because a generic Home Factory can store EJBHome objects in a collection, testing them first and returning them without creating the actual remote reference, so it does not need to know the specific EJB, allowing the specific client code to cast the generic Object to the specific EJBHome object.
A Sun-certified instructor once told me that it was absolutely necessary to use the Object returned from the narrow method because it performed some essential RMI activity on the object, but I have never had a problem using it the second way I describe above in the HomeFactory. Also, I have never been able to find any documentation to substantiate his claim. Any thoughts as to the necessity of using the object returned from the narrow method? It appears to be the exact same object that is passed in to the method, and likely un-changed at that.

The narrow method is there to allow an implementation to do some extra work or return a different object if it needs to. It appears that your implementation does not need to do these things so it just returns the object that was passed. If you take your shortcut, you will limit yourself to running only on your current implementation. If you try to switch implementations or even upgrade to a later version it might break. If you follow the correct method the your code will be portable.

Confusion in PortableRemoteObject.narrow() method

In EJB 1.0 reference of home object is obtained through external casting as HelloHome home = (HelloHome)ctx.lookup("HelloHome")
My question is that since IIOP has not been designed for Java, but for generic languages, and this means that there are some limitations. Some languages, in fact, do not have the concept of casting.
Still why we have to cast the Object if we use PortableRemoteObject.narrow method for obtaining the home interface reference in EJB2.0.
HelloHome home = (HelloHome)javax.rmi.PortableRemoteObject.narrow(object, HelloHome.class)

If the client is built using Java, you can not explicitly cast from the Naming.lookup() function. Instead, you must use lookup() to return a generic java.lang.Object, and then cast to the specific object type with the PortableRemoteObject.Narrow(objectReference, interfaceName) method.

How to solve PortableRemoteObject.narrow exception

Hi ,
I am getting portableRemoteObject exception... when i tried to narrow the stub with home class.
Please find my code:
Object objRef = ctx.lookup("java:comp/env/ejb/ejbSchedularBean"
TaskHandlerHome home = (TaskHandlerHome) javax.rmi.PortableRemoteObject.narrow(objRef,TaskHandlerHome.class);
Please help me to solve.
cannot cast class com.ibm.websphere.schedular._TaskHandlerHome_Stub to interface com.ibm.websphere.scheduler.TaskHandlerHome
     at com.ibm.rmi.javax.rmi.PortableRemoteObject.narrow(PortableRemoteObject.java:396)
     at javax.rmi.PortableRemoteObject.narrow(PortableRemoteObject.java:156)
     at com.ibm.websphere.schedular.CallBeanTask.getBeanClassInstance(CallBeanTask.java:66)
     at com.sched.servlet.SchedulerServlet.init(SchedulerServlet.java:25)
     at javax.servlet.GenericServlet.init(GenericServlet.java:256)
     at com.ibm.ws.webcontainer.servlet.ServletWrapper.init(ServletWrapper.java:185)
     at com.ibm.ws.wswebcontainer.servlet.ServletWrapper.init(ServletWrapper.java:316)
     at com.ibm.ws.webcontainer.servlet.ServletWrapper.initialize(ServletWrapper.java:1119)
     at com.ibm.ws.wswebcontainer.servlet.ServletWrapper.initialize(ServletWrapper.java:149)
     at com.ibm.wsspi.webcontainer.extension.WebExtensionProcessor.createServletWrapper(WebExtensionProcessor.java:99)
     at com.ibm.ws.webcontainer.webapp.WebApp.getServletWrapper(WebApp.java:742)
     at com.ibm.ws.webcontainer.webapp.WebApp.initializeTargetMappings(WebApp.java:422)
     at com.ibm.ws.webcontainer.webapp.WebApp.commonInitializationFinish(WebApp.java:275)
     at com.ibm.ws.wswebcontainer.webapp.WebApp.initialize(WebApp.java:272)
     at com.ibm.ws.wswebcontainer.webapp.WebGroup.addWebApplication(WebGroup.java:88)
     at com.ibm.ws.wswebcontainer.VirtualHost.addWebApplication(VirtualHost.java:157)
     at com.ibm.ws.wswebcontainer.WebContainer.addWebApp(WebContainer.java:655)
     at com.ibm.ws.wswebcontainer.WebContainer.addWebApplication(WebContainer.java:608)
     at com.ibm.ws.webcontainer.component.WebContainerImpl.install(WebContainerImpl.java:333)
Regards.
sur

I have created a simple applet.
import java.lang.*;
import java.awt.*;
public class jawtex3 extends java.applet.Applet
public void init()
add(new Button("One"));
add(new Button("Two"));
public Dimension preferredSize()
return new Dimension(200, 100);
public static void main(String [] args)
Frame f = new Frame(" jawtex3");
jawtex3 ex = new jawtex3();
ex.init();
f.add("Center", ex);
f.pack();
f.show();
In this no compilation errors.
I am getting runtime exception.as Exception in thread "main"java.lang.NoClassDefFound Error: jawtex
reply me soon.
thankyou.

Javax.rmi.portableRemoteObject.narrow

Hi
Pls tell me why we narrow the instance of the object we looked up,
before type casting it to a home referance by using javax.rmi.portableRemoteObject.narrow(Object,Home.class)

In the early days of EJB this call was required to ensure portability due to some intracacies of how
RMI-IIOP and CORBA ORBs are implemented. Some implementations are able to directly return
the correctly typed object from the lookup, but in others the extra PortableRemoteObject.narrow
call is necessary, so always using it ensures portability.
Starting in Java EE 5, PortableRemoteObject.narrow is not needed if the code is either accessing
a Remote 3.0 Business Interface or if the code is accessing a 2.x style Home object using
@EJB or the new EJBContext.lookup method.
--ken

ClassCastException with PortableRemoteObject.narrow call

I want to call an ejb component located on a different machine and I can not get it to work. So I tried to deploy it under my version of jboss and try to invoke it. I was able to call it but when I added Context.PROVIDER_URL to my properties I get a classCastException.
String host = "jnp://localhost:1099";
props.setProperty(Context.PROVIDER_URL, host);
I started getting the following exception
2006-11-03 10:17:18,319 ERROR [STDERR] java.lang.ClassCastException
2006-11-03 10:17:18,319 ERROR [STDERR] at com.sun.corba.se.impl.javax.rmi.PortableRemoteObject.narr
ow(PortableRemoteObject.java:229)
2006-11-03 10:17:18,319 ERROR [STDERR] at javax.rmi.PortableRemoteObject.narrow(PortableRemoteObjec
t.java:137)
As soon as I uncomment that props.setProperty(Context.PROVIDER_URL, host);
line everything works fine.
I have seen this type of exception before when I tried invoking the ejb on a different computer as well. When I inspect the object with reflection I see that it found the right interface.
This is my code again:
Properties props = new Properties();
props.setProperty(Context.INITIAL_CONTEXT_FACTORY,"org.jboss.security.jndi.JndiLoginInitialContextFactory");
props.setProperty(Context.SECURITY_PRINCIPAL, "admin");
props.setProperty(Context.SECURITY_CREDENTIALS, "admin");
props.put(javax.naming.Context.URL_PKG_PREFIXES, "org.jboss.naming:org.jnp.interfaces");
String host = "jnp://localhost:1099";
props.setProperty(Context.PROVIDER_URL, host);
ctx = new InitialContext( props );
Object object = ctx.lookup( "ejb/com/blah/Manager" );
ManagerRemoteHome home = (ManagerRemoteHome)PortableRemoteObject.narrow ( object, ManagerRemoteHome.class);
ManagerRemote manager = home.create();
Thanks

1099 is the RMI/JRMP Registry. You are using RMI/IIOP. Is this port number really correct?

Classcastexception on portableremoteobject narrow

I was successfully connecting to an EJB on my WebLogic server from a Java
IDL client using the iiop protocol, cosnaming initialcontextfactory. I'm at
a loss as to what is different now that is causing this to fail. I'm sure
it has something to do with how I'm generating the stubs and/or the
client/server classpath, but can't see what I'm doing wrong now. My steps
are as follows.
1) Create the EJB jar (call it jar1) using weblogic.ejbc
2) Run jar1 through weblogic.ejbc using -idl -iiop, creating jar2
3) Deploy jar2 in the java client's classpath
I get the initial context fine, but when I get to this line:
_home = (myHome)(PortableRemoteObject.narrow(ctx, myHome.class));
I get the following error:
java.lang.ClassCastException
at
com.sun.corba.se.internal.javax.rmi.PortableRemoteObject.narrow(PortableRemo
teObject.java:296)
Can anyone give me some assistance?
Thx!
Sandy Barletta

Ok, here's what's going on here. The problem happens when I use
com.sun.jndi.cosnaming.CNCtxFactory as my initial context factory. After the
lookup of the home interface, what I get back in my context object if I call
getClass().getName() is the following:
com.sun.jndi.cosnaming.CNCtx
The class cast exception occurs when I try to narrow this to my home
interface.
If I use weblogic.jndi.WLInitialContextFactory instead of
com.sun.jndi.cosnaming.CNCtxFactory, what I get back in my context object if
I call getClass().getName() is
com.sun.corba.se.internal.iiop.CDRInputStream$1 and the narrow succeeds.
What gives? Do I have to use the weblogic context factory? I was hoping to
avoid the need for weblogic packages on the client. Also, our whole reason
for using IIOP was to avoid compatibility problems between weblogic servers
running at different version levels. If I have to use the weblogic context
factory, and we have a weblogic client running at a different version from
the server, will there be problem?
Sandy Barletta
"Sandy Barletta" <[email protected]> wrote in message
news:[email protected]...
I was successfully connecting to an EJB on my WebLogic server from a Java
IDL client using the iiop protocol, cosnaming initialcontextfactory. I'mat
a loss as to what is different now that is causing this to fail. I'm sure
it has something to do with how I'm generating the stubs and/or the
client/server classpath, but can't see what I'm doing wrong now. My steps
are as follows.
1) Create the EJB jar (call it jar1) using weblogic.ejbc
2) Run jar1 through weblogic.ejbc using -idl -iiop, creating jar2
3) Deploy jar2 in the java client's classpath
I get the initial context fine, but when I get to this line:
_home = (myHome)(PortableRemoteObject.narrow(ctx, myHome.class));
I get the following error:
java.lang.ClassCastException
at
com.sun.corba.se.internal.javax.rmi.PortableRemoteObject.narrow(PortableRemo
teObject.java:296)
Can anyone give me some assistance?
Thx!
Sandy Barletta

PortableRemoteObject.narrow throws ClassCastException

Hi Friends,
I am trying to access home interface of a stateless session EJB from an Applet running in JRE 1.3.1 in IE. My EJB is running in WebLogic Server 6.1. I am getting a cast error while narrowing the remote home interface. My server and client are running on the same machine though they are in different JVMs. I was able to access this remote home interface in a simple test program running from command line.
This session bean accesses other entity beans deployed in the same WebLogic server, if that has anything to do with it.
Following is the error callstack:
java.lang.ClassCastException
at com.sun.corba.se.internal.javax.rmi.PortableRemoteObject.narrow(PortableRemoteObject.java:296)
at javax.rmi.PortableRemoteObject.narrow(PortableRemoteObject.java:137)
Any help in resolving this issue will be greatly appreciated.
Thanks,
Krishna.

Hello
I have same problem in Java Web Start.
This Situation is same.
I report the result of my investigation.
I'm having a problem in lookup remote object when using JWS.
My application runs normally in Java Application without JWS.
I'm using BEA WebLogic Server 6.1.
My application acts in EJB client application.
But my application runs normally in WebLogic Server 6.0 and JWS.
When I cast remote object to my interface, I encountered this kind of error.
java.lang.ClassCastException
at com.sun.corba.se.internal.javax.rmi.PortableRemoteObject.narrow
at javax.rmi.PortableRemoteObject.narrow
While using WebLogic Server 6.0, I include stub classes in my jar file.
But in WebLogic Server 6.1, ejbc does not generate stub classes.
WebLogic uses Dynamic proxy technology in JDK 1.3 for this purpose.
So, EJB client conflict with sand box security policy...
When I add the following line to javaws.policy file,
my application runs without problem.
permission java.io.SerializablePermission "enableSubstitution";
Is everyone suffering from this kind of problem?
Is this problem improved in the future?
I need more information about this problem.
I am not sure, this is specification.
Thanks in advance
Hiroki

PortableRemoteObject.narrow Problem

Hello, I have a jsp that is talking to a servlet that is suppose to connect to a stateless session bean in 9.0.3. The bean deploys fine. I continue to get the following error when the servlet tries to talk to the bean. The servlet works fine on JRun 4 talking to the same bean. Here is my code.
Hashtable env = new Hashtable();
env.put(Context.PROVIDER_URL, "ormi://141.254.22.145:23791/JRun2");
env.put(Context.INITIAL_CONTEXT_FACTORY, "com.evermind.server.rmi.RMIInitialContextFactory");
env.put(Context.SECURITY_PRINCIPAL, "admin");
env.put(Context.SECURITY_CREDENTIALS, "admin");
env.put(Context.URL_PKG_PREFIXES, "com.evermind.naming");
Context context = new InitialContext(env);
System.out.println("context: " + context.getEnvironment().toString());
Object o = (Object) context.lookup("SessionManagerLiteStateless");
System.out.println("o: " + o.toString());
sessionManagerLiteStatelessHome = (SessionManagerLiteStatelessHome)PortableRemoteObject.narrow(o, SessionManagerLiteStatelessHome.class);
The context outputs the Home interface fine but it bombs on sessionManagerLiteStatelessHome = (SessionManagerLiteStatelessHome)PortableRemoteObject.narrow(o, SessionManagerLiteStatelessHome.class);
Here is the error.
java.lang.ClassCastException
at com.sun.corba.se.internal.javax.rmi.PortableRemoteObject.narrow(Unkno
wn Source)
at javax.rmi.PortableRemoteObject.narrow(Unknown Source)
at JRun2.OracleServlet.init(OracleServlet.java:30)
at com.evermind.server.http.HttpApplication.loadServlet(HttpApplication.
java:1956)
at com.evermind.server.http.HttpApplication.findServlet(HttpApplication.
java:4355)
at com.evermind.server.http.HttpApplication.getRequestDispatcher(HttpApp
lication.java:2184)
at com.evermind.server.http.HttpRequestHandler.processRequest(HttpReques
tHandler.java:617)
at com.evermind.server.http.HttpRequestHandler.run(HttpRequestHandler.ja
va:259)
at com.evermind.server.http.HttpRequestHandler.run(HttpRequestHandler.ja
va:106)
at EDU.oswego.cs.dl.util.concurrent.PooledExecutor$Worker.run(PooledExec
utor.java:803)
at java.lang.Thread.run(Unknown Source)

Michael -
That looks like a correct set of calls to me.
Can I ask what environment are you running in? An OC4J standalone or a 9iAS environment?
** If this is a 9iAS environment, then the port number for the ORMI lookup will be different than 23791. The actual ORMI port number for a 9iAS instance is dynamically allocated when the OC4J processes are started. The defdault port ranges for ORMI are 3000-3100 by default. The process manager starts at the lower bound and works it's way sequentially along until a free port is found. So usually for the OC4J_Home instance, the ORMI port is 3000.
I've never used the URL_PKG_PREFIXES myself, what happens if you remove that entry for the Hashtable?
-steve-

PortableRemoteObject.narrow causes NoClassDefFoundError

I exhaustively searched for this error in this, and other forums, and
tried some suggested techniques, but none worked.
/* Following causes NoClassDefFoundError */
Entity1RemoteHome printHome = (Entity1RemoteHome)
     PortableRemoteObject.narrow( prrefHome, Entity1RemoteHome.class );
RemoteClient1.java contains:
     package com.zbeans;
     import com.zbeans.Entity1Remote;
     import com.zbeans.Entity1RemoteHome;
     import javax.naming.InitialContext;
     Context prinitctx = new InitialContext();
     Context prenvctx = (Context) prinitctx.lookup("java:comp/env");
     /* 'ejb/Entity1 EJB ref1' is the Reference Name appearing under the JNDI
          Names tab under the application object, for the deployment tool. */
     Object prrefHome = prenvctx.lookup("ejb/Entity1 EJB ref1");
     /* Following causes NoClassDefFoundError */
     Entity1RemoteHome printHome = (Entity1RemoteHome)
          PortableRemoteObject.narrow( prrefHome, Entity1RemoteHome.class );
     Binding name:`java:comp/env/ejb/Entity1 EJB ref1`
     RemoteClient1.main(): NoClassDefFoundError has occurred!!
     getMessage(): com.zbeans.Entity1RemoteHome
     toString(): java.lang.NoClassDefFoundError: com.zbeans.Entity1RemoteHome
     I ran using C:\j2sdkee1.3.1\bin>runclient -client D:\zJava\zsamples\EJB\application1\application1.ear -name RemoteClient1 -textauth
     I ensured j2ee and cloudscape were running, and
     set APPCPATH=application1Client.jar     (application1Client.jar was generated by the deployment tool)
Entity1RemoteHome.java contains:
     package com.zbeans;
     import java.rmi.RemoteException;
     import javax.ejb.*;
     public interface Entity1RemoteHome extends javax.ejb.EJBHome {
     public Entity1Remote create (Integer id)
          throws CreateException, RemoteException, EJBException;
Remote1Client1, Entity1RemoteHome.java, etc. resides under
C:\JRun4\servers\default\default-ear\default-war\WEB-INF\classes\com\zbeans
I was thinking of moving RemoteClient1.java one level higher in the
directory tree. But maybe this is not necessary since the sample
Converter app. has the client in the same folder as the EJB interfaces?
- should I move the .java, and .class files from c:\jrun4\...\classes\com\zbeans
     to D:\zJava\zsamples\EJB\application1\com\zbeans since this is where the
     .ear, .jar are generated?
My environment settings are:
     java version "1.4.0_01"
     Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0_01-b03)
     Java HotSpot(TM) Client VM (build 1.4.0_01-b03, mixed mode)
     WinNT 4.0 SP5
     CLASSESDIR=c:\j2sdkee1.3.1\lib\classes
     CLASSPATH=.;c:\j2sdkee1.3.1\lib\j2ee.jar;D:\jakarta-tomcat-3.3.1\lib\common\serv
     let.jar;C:\JRun4\servers\default\default-ear\default-war\WEB-INF\classes;D:\zJav
     a\zsamples\EJB\application1
     J2EEJARS=c:\j2sdkee1.3.1\lib\j2ee.jar
     J2EETOOL_CLASSES=c:\j2sdkee1.3.1\lib\toolclasses
     J2EETOOL_JAR=c:\j2sdkee1.3.1\lib\j2eetools.jar
     J2EE_HOME=c:\j2sdkee1.3.1
     JAVA_HOME=C:\j2sdk1.4.0_01
     etc.

Refer to
http://access1.sun.com/FAQSets/ejbfaq.html#17

Sun One EJB problem - PortableRemoteObject.narrow ClassCastException...

Hi all,
I'm using Sun One app server 7 for the first time and am having a bit of difficulty. I have deployed a very simple EAR containing one stateless session bean just to test it. The ear appears to have deployed correctly but PortableRemoteObject.narrow is throwing a ClassCastException when trying to do a remote lookup on the bean.
I'm using the following env settings...
initialContextFactory = com.sun.enterprise.naming.SerialInitContextFactory
providerUrl = iiop://127.0.0.1:3700The lookup appears to work okay - this line of code executes successfully
Object objref = initialContext.lookup(jndiHomeName);...objref appears to initalise succesfully (if I toString() it I get an iiop stream of some sort). However, it is the next line that is failing...
Object obj = PortableRemoteObject.narrow(objref, homeClass);...this is the exception I get...
java.lang.ClassCastException
     at com.sun.corba.se.internal.javax.rmi.PortableRemoteObject.narrow(Unknown Source)
     at javax.rmi.PortableRemoteObject.narrow(Unknown Source)
     at com.scorlog.ServiceLocator.getRemoteHome(ServiceLocator.java:145)Furthermore, when PortableRemoteObject.narrow() executes, I get the following console exception on the server...
com.sun.corba.ee.internal.core.DuplicateServiceContext
        at com.sun.corba.ee.internal.core.ServiceContexts.put(ServiceContexts.java:208)
        at com.sun.corba.ee.internal.iiop.ServerRequestImpl.getServiceContextsForReply(ServerRequestImpl.java:258)
        at com.sun.corba.ee.internal.iiop.ServerRequestImpl.createResponse(ServerRequestImpl.java:89)
        at com.sun.corba.ee.internal.POA.SubcontractResponseHandler.createReply(SubcontractResponseHandler.java:50)
        at org.omg.CosNaming.NamingContextExtPOA._invoke(NamingContextExtPOA.java:377)
        at com.sun.corba.ee.internal.POA.GenericPOAServerSC.dispatchToServant(GenericPOAServerSC.java:569)
        at com.sun.corba.ee.internal.POA.GenericPOAServerSC.internalDispatch(GenericPOAServerSC.java:211)
        at com.sun.corba.ee.internal.POA.GenericPOAServerSC.dispatch(GenericPOAServerSC.java:113)
        at com.sun.corba.ee.internal.iiop.ORB.process(ORB.java:275)
        at com.sun.corba.ee.internal.iiop.RequestProcessor.process(RequestProcessor.java:83)
        at com.iplanet.ias.corba.ee.internal.iiop.ServicableWrapper.service(ServicableWrapper.java:25)
        at com.iplanet.ias.util.threadpool.FastThreadPool$ThreadPoolThread.run(FastThreadPool.java:288)
        at java.lang.Thread.run(Thread.java:534)
FINE: No SAS context element found in service context listI have seen the forum that other users have had similar problems and the suggestion was that the client can't see the ejb stubs. I don't think this is the problem in my case as I deployed the same ear on weblogic 7 (obviously substituting sun-ejb-jar.xml for a weblogic-ejb-jar.xml) and successfully executed the same client code for the remote lookup.
My feeling is that the problem revolves around the JNDI binding. Could it be the case that even though the object is binding properly, the app server doesn't realise it is an ejb and not a jdbc/jms/mail object? The documentation gives details on looking up a JDBC, javamail, URL, JMS resource (http://docs.sun.com/source/817-2177/djjndi.html) but not ejb so I could be doing something simple wrong here...
My sun-ejb-jar.xml is as follows....
<?xml version="1.0" encoding="UTF-8"?>

<sun-ejb-jar>
    <enterprise-beans>
        <ejb>
            <ejb-name>SBTest</ejb-name>
            <jndi-name>ejb/SBTestBean</jndi-name>
        </ejb>
    </enterprise-beans>
</sun-ejb-jar>However, I noticed on another thread, a user had some additional elements under their <ejb> tag like this...
<?xml version="1.0" encoding="UTF-8"?>
<sun-ejb-jar>
<enterprise-beans>
    <name>Ejb1</name>
    <ejb>
      <ejb-name>HelloBean</ejb-name>
      <jndi-name>HelloBean</jndi-name>
      <ejb-ref>
        <ejb-ref-name>ejb/helloBean</ejb-ref-name>
        <jndi-name>HelloBean</jndi-name>
      </ejb-ref>
    </ejb>
</enterprise-beans>
</sun-ejb-jar>However, when I tried to add and <ejb-ref> element to my xml doc the ear failed to deploy. This is the error I get in the admin console...
Error
Deployment Error -- Error while running ejbc -- Fatal Error from EJB Compiler -- --
Failed to load deployment descriptor for: testApp cause: Error converting J2EE-
specific ejb xml to object representation: testApp.jar app_testApp Generated by
XDoclet This bean has no ejb reference by the name of [ejb/SBtest]
ejb/SBTestSBTestThis problem is eating up my time and being made all the more frustrating by the fact that a) it deploys on weblogic and b) the documentation is terrible. Even the sample application that comes with sun one only provides the .class files for the code that does the ejb look up and not the .java so you can't see how they hell they do it!
Unfortunately I am tied to using Sun One so I really need to solve this problem fast. If anyone can provide any help I'd greatly appreciate it.
Cheers,
John :)

I am having the same problem after upgrading to Sun One from iplanet. Any clue?

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What is the exact error message you're getting?

PortableRemoteObject.narrow(...) error , why?

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