Hello world example using EJB 3

[rajiv raghunandan]

I just started reading EJB 3 and tried executing a simple Hello world example but ran into some problems. I am using Eclipse along with Weblogic server 10.
I created an EJB project and within it I created a stateless session bean with a remote interface.
The code for the interface is

  
package com.example;
import javax.ejb.Remote;

@Remote
public interface HelloWorldRemote {
   public void hello(String name);
}
  

The code for the bean is

  
package com.example;

import javax.ejb.Stateless;

/**
 * Session Bean implementation class HelloWorld
 */
@Stateless(mappedName="/HelloWorld123")
public class HelloWorld implements HelloWorldRemote {

    /**
     * Default constructor. 
     */
    public HelloWorld() {
        // TODO Auto-generated constructor stub
    }

	@Override
	public void hello(String name) {
		// TODO Auto-generated method stub
		System.out.println("Hello "+name);
		
	}

}
  

The client code is as follows

   
import java.util.Properties;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import com.example.HelloWorldRemote;

public class Client {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub

		Properties prop = new Properties();
		prop.put(Context.INITIAL_CONTEXT_FACTORY, "weblogic.jndi.WLInitialContextFactory");
		prop.put(Context.PROVIDER_URL, "t3://localhost:7001");
		try {
			Context ctx = new InitialContext(prop);
			HelloWorldRemote hello = (HelloWorldRemote)ctx.lookup("HelloWorld123#com.example.HelloWorld");
			hello.hello("sandeep");
		} catch (NamingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}

}
 

I get the following exception

   
Exception in thread "Main Thread" java.lang.NoClassDefFoundError: weblogic/kernel/KernelStatus
	at weblogic.jndi.Environment.<clinit>(Environment.java:78)
	at weblogic.jndi.WLInitialContextFactory.getInitialContext(WLInitialContextFactory.java:117)
	at javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:667)
	at javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:288)
	at javax.naming.InitialContext.init(InitialContext.java:223)
	at javax.naming.InitialContext.<init>(InitialContext.java:198)
	at com.client.Client.main(Client.java:25)
 

The session bean is getting deployed on the server without any issues and I am able to see it in the deployment list. I am unsure if there is a need for me to use the properties within the client and if thats a reason for the exception. Can anyone help me out in telling me what I am doing wrong . Also can anyone tell me if the format I am using in the lookup is correct.

[rajiv raghunandan]

also i forgot to mention that i included weblogic.jar in the build path and i am deploying the session bean directly onto the weblogic server through eclipse

[S Sravs]

rajiv raghunandan wrote:also i forgot to mention that i included weblogic.jar in the build path and i am deploying the session bean directly onto the weblogic server through eclipse

Hi did you find the solution please let me know,i am getting the same problem with same constraints
Thanks
Sravs

[Michael Drona]

Here's an example I have that works

Hello.java

package org.acme;

import javax.ejb.SessionBean;
import javax.ejb.Remote;

@Remote
public interface Hello {
        public String sayHello();

        public void helloWait() throws Exception;
}

HelloBean.java

package org.acme;

import java.rmi.RemoteException;
import javax.ejb.CreateException;
import javax.ejb.EJBException;
import javax.ejb.SessionBean;
import javax.ejb.SessionContext;

import javax.ejb.Stateless;

@Stateless(name="HelloBean", mappedName="HelloBean")
public class HelloBean implements Hello {
        public String sayHello(){
                String str = "Hello World";
                System.out.println(str);
                return str;
        }

        public void helloWait() throws Exception
        {
                Thread.sleep(5000);
        }
}

HelloClient.java

package org.acme;

import java.util.Properties;
import javax.naming.InitialContext;
import javax.naming.Context;
import javax.rmi.PortableRemoteObject;

//import examples.TestSessionBean;

public class HelloClient{
        public static void main(String[] args) throws Exception{
                Properties props = new Properties();
                props.put(Context.INITIAL_CONTEXT_FACTORY,"weblogic.jndi.WLInitialContextFactory");
                props.put(Context.PROVIDER_URL,"t3://127.0.0.1:7001");

                Context ctx = new InitialContext(props);
                Object ref = ctx.lookup("HelloBean#org.acme.Hello");

                Hello h = (Hello)PortableRemoteObject.narrow(ref, Hello.class);
                String result;

                result = h.sayHello();
                System.out.println(result);

                h.helloWait();

                result = h.sayHello();
                System.out.println(result);
        }
}

compress the whole org thing into a jar
jar cvf hello.jar org

deploy the jar on the wl server and then run the client.

[S Sravs]

Hey
I am working on Eclipse and Weblogic. In eclipse i didn't remove the Weblogic libraries while debugging so i got that exception
Thanks
Sravanthi