在简单的Java类中访问远程企业bean

Question

Here's my Java class

import endpoint.NewSessionRemote;
import javax.naming.Context;
import javax.naming.InitialContext;

public class HelloClient {

    public static void main(String[] args) {
        try {
            Context ctx = new InitialContext();
            NewSessionRemote hello = (NewSessionRemote) ctx.lookup("endpoint.NewSessionRemote");
            System.out.println(hello.stringChange(4));
        } catch (Exception ex) {
            ex.printStackTrace();
        }

    }
}

When I run this class I'm getting an exception.

    javax.naming.NameNotFoundException: endpoint.NewSessionRemote not found
        at com.sun.enterprise.naming.TransientContext.doLookup(TransientContext.java:216)
        at com.sun.enterprise.naming.TransientContext.lookup(TransientContext.java:188)
        at com.sun.enterprise.naming.SerialContextProviderImpl.lookup(SerialContextProviderImpl.java:74)
        at com.sun.enterprise.naming.RemoteSerialContextProviderImpl.lookup(RemoteSerialContextProviderImpl.java:129)
        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 com.sun.corba.ee.impl.presentation.rmi.ReflectiveTie._invoke(ReflectiveTie.java:154)
        at com.sun.corba.ee.impl.protocol.CorbaServerRequestDispatcherImpl.dispatchToServant(CorbaServerRequestDispatcherImpl.java:687)
        at com.sun.corba.ee.impl.protocol.CorbaServerRequestDispatcherImpl.dispatch(CorbaServerRequestDispatcherImpl.java:227)
        at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.handleRequestRequest(CorbaMessageMediatorImpl.java:1846)
        at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.handleRequest(CorbaMessageMediatorImpl.java:1706)
        at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.handleInput(CorbaMessageMediatorImpl.java:1088)
        at com.sun.corba.ee.impl.protocol.giopmsgheaders.RequestMessage_1_2.callback(RequestMessage_1_2.java:223)
        at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.handleRequest(CorbaMessageMediatorImpl.java:806)
        at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.dispatch(CorbaMessageMediatorImpl.java:563)
        at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.doWork(CorbaMessageMediatorImpl.java:2567)
        at com.sun.corba.ee.impl.orbutil.threadpool.ThreadPoolImpl$WorkerThread.run(ThreadPoolImpl.java:555)
java.lang.NullPointerException

All the other enterprise bean classes are written according to the EJB 3.0 standard. Your valuable contribution is expected.

Solution

The exception was

javax.naming.NameNotFoundException: endpoint.NewSessionRemote not found

It occurs because the JNDI name that was given by the application side didn't match the servser's (Glassfish) actual JNDI name, so I did was check the JNDI tree in Glassish through its admin console (vendor specific) and I did notice that the JNDI for the NewSessionRemote interface (which is the business interface of the session bean NewSessionBean ) is different from the name which I have given in the application side. So how did this happen then suddenly something came in to my mind that's the ejb-jar.xml there is another name JNDI name assigned to the same NewSessionRemote using tag. So I simply remove it and redeploy EJB module. That's it.

Answer 1

Looks like you have no RMI registry (ie active server) you are lookingUp() against.

You supplied no Context.INITIAL_CONTEXT_FACTORY variable, so the lookup should be a valid URL, which it is not.

Hence, you should put something like this on your env (on the iCtx ):

env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.rmi.registry.RegistryContextFactory");

I suggest you read the the simple examples over at http://java.sun.com/j2se/1.5.0/docs/guide/jndi/jndi-rmi.html

Answer 2

When using JNDI, you're using an API that requires a specific configuration underlying it in order to connect to the server (see the Javadoc for details on what that configuration is). For example, java.naming.factory.initial is the property which indicates which implementation of JNDI you want to use.

Now, when running code inside a JavaEE server, this configuration is available implicitly, and all you need to do is what you have done in your code - instantiate InitialContext , and perform a lookup. However, when running outside the server, this implicit configuration is not present, and so you need to configure your InitialContext explicitly.

Your sample code uses a main() method, which suggests that you're running outside the container. The config you need will depend on your specific application server, you'll need to look up that documentation to see what config to supply.