always showing null, not calling the bean class methods.

[Punit Jain]

i m getting a problem in stateless bean..
here is my interface:
calc.java

package ejb;
import javax.ejb.Local;
@Local
public interface calc {
public float sum(float a,float b);
public float mult(float a,float b);
public float minus(float a,float b);
public float div(float a,float b);
}

calcImpl.java

package ejb; 
import javax.ejb.Stateless;
@Stateless(mappedName="Firstcalc")
public class calcImpl implements calc 
{
	public float sum(float a,float b)
	{
		System.out.println("going into sum");
		return a+b; 
	}	
	public float mult(float a,float b)
	{ System.out.println("going into mult");
		return a*b; 
	}
	public float minus(float a,float b)
	{ System.out.println("going into minus");
		return a-b; 
	}
	public float div(float a,float b) 
	{System.out.println("going into div");
		try {
			return a/b;}
		catch(Exception e)
		{
			System.out.println("Error:devision by 0!!");
			return 0;
		}
	}
}

Index.jsp

<%int a=2,b=1;
if (request.getAttribute("a")!=null)
	a=Integer.parseInt(request.getAttribute("a").toString());
if( request.getAttribute("b")!=null)
	b=Integer.parseInt(request.getAttribute("b").toString());%>
	<form method="get" action="calServlet">
	<b>Number 1:</b><input type='text' name='n1' value="<%=a%>" /> <br/>
	<b>Number 2:</b><input type='text' name='n2' value="<%=b%>" /> <br/>
	<u><b>Options:</b></u> <br/>
	<ul>
	<li><b>+</b><input type='radio' name="oper" value='+' checked /></li>
	<li><b> -</b><input type='radio' name="oper" value='-' /></li>
	<li><b>*</b><input type='radio' name="oper" value='*' /></li>
	<li>  <b>/</b><input type='radio' name="oper" value='/' /></li> </ul>
	<b>-------------------------------------------</b> <br/>
	<input type="submit" value="Executer" /> 
	</form>
	<font color='blue'><b>Result is: </b> <%=session.getAttribute("result")%> </font> <br/>
	<font color='red' >Error: <%=session.getAttribute("error")%></font>

calServlet.java

package web;
import java.io.IOException;
import javax.naming.*;
import javax.servlet.*;
import javax.servlet.*;
import javax.servlet.http.*;
import ejb.calc;
public class calServlet extends HttpServlet {
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		HttpSession session=request.getSession(true);
		RequestDispatcher rd=this.getServletContext().getRequestDispatcher("/Index.jsp");
		float a=Float.parseFloat(request.getParameter("n1"));
		float b=Float.parseFloat(request.getParameter("n2"));
		char oper=request.getParameter("oper").charAt(0);
		float result=0;
		try {
			Context ctx=new InitialContext();// call the calcImpl class of the SimpleCalculator EJB with the mappedNamecalc 
		calc cl=(calc) ctx.lookup("Firstcalc");
		switch(oper){
		case '+': result=cl.sum(a, b); break;
		case '-': result =cl.minus(a, b); break;
		case '*': result =cl.mult(a, b); break;		 
		case '/': result =cl.div(a, b);		 
		break;
		}
		session.setAttribute("result",result);
		request.setAttribute("a", a);
		request.setAttribute("b", b);
		}catch(NamingException e)
		{
			session.setAttribute("erreur: ",e.getMessage());
		}rd.forward(request,response);		
	}
}

the problem is my servlet is not calling the methods of calcImpl class.
i mean when i clicking on button, it showing me null always..

[James Boswell]

What properties are set for your context? See here for more info: http://docs.oracle.com/javase/6/docs/api/javax/naming/InitialContext.html

[Punit Jain]

What properties are set for your context?

Where to check this??
i don't know about them, i just got the code from internet.

[James Boswell]

Did you read anything from the link I sent you? Do this first. I prefer the jndi.properties file option myself.

[Punit Jain]

yes, i read that, but didn't got anything.
how that is related to this problem?
i mean what is the use of this:

What properties are set for your context? See here for more info: http://docs.oracle.com/javase/6/docs/api/javax/naming/InitialContext.html

here?

[James Boswell]

Punit

If you had bothered to read the link more carefully, you will have discovered that it is totally relevant to what you are trying to achieve. When you use an InitialContext, a particular set of system properties need to be set so that this class knows where to look for the resources you are attempting to look up.

The values of these system properties vary, depending on the application server you are using. But recently, when looking up an EJB remotely, running on JBoss AS6, I used the following values defined in a jndi.properties file:

java.naming.factory.initial=org.jnp.interfaces.NamingContextFactory
java.naming.provider.url=localhost:1099
java.naming.factory.url.pkgs=org.jboss.naming: org.jnp.interfaces

You may need to look up the documentation of the application server you are using to find out what values are required.

[mihran eprem]

on witch j2ee container did you deploy your application ??
if weblogic you cant look up in this way ....

[Punit Jain]

no i used jboss..