How to conduct a lookup of an EJB from a servlet context? - servlets

Question

I have a POJO that was instantiated from a servlet. I need to make a lookup of an EJB within this POJO, either CDI or JNDI. My JEE container is TomEE 1.6.0.
My question is this: need the EJB have remote interface? Because if I instantiate it directly from the servlet by #EJB the remote interface does not need...
Just see this simple example which always throws NameNotFoundException.
#Stateless
public class MyEJB
{
public String sayHello()
{
return "Hello";
}
}
The next servlet try yo lookup MyEJB:
#WebServlet("/myServlet")
public class MyServlet extends HttpServlet
{
private static final long serialVersionUID=1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException,IOException
{
try
{
Context ctx = new InitialContext();
MyEJB ejb = (MyEJB) ctx.lookup("MyEJB");
System.out.println(ejb.sayHello());
}
catch(Exception ex)
{
ex.printStackTrace();
throw new RuntimeException(ex);
}
}
}
The line: MyEJB ejb = (MyEJB) ctx.lookup("MyEJB"); always throws NameNotFoundException. But if I use #EJB it work fine. But I need do the lookup in JNDI mode because finally I will instantiate this EJB within a POJO.
So, why fails this lookup ?

Answer 1

This has nothing to do with remote interfaces.
When you declare MyEJB in servlet using #EJB it works, because servlet is container-managed - your TomEE server instantiates servlet object. However declaration of MyEJB in MyPojo (also using #EJB) won't work, because MyPojo is not container-managed - it is created using new MyPojo(), not by TomEE server.
You could for example make MyPojo another EJB (using #Stateless) and inject it using #EJB to the servlet - not by creating new MyPojo().

Answer 2

I can solve this problem by myself by instrospecting the JNDI tree with this simple class:
import javax.naming.Binding;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NameClassPair;
import javax.naming.NamingEnumeration;
public class JndiInstrospector
{
public static void print()
{
try
{
Context ctx = new InitialContext();
String n = ctx.getNameInNamespace();
_print(n);
}
catch(Exception ex)
{
ex.printStackTrace();
throw new RuntimeException();
}
}
private static void _print(String name) throws Exception
{
try
{
System.out.println("Name in manespace: "+name);
Context ctx = new InitialContext();
NamingEnumeration<Binding> list = ctx.listBindings(name);
while( list.hasMoreElements() )
{
Binding b = list.nextElement();
String s = b.getName();
_print(name+"/"+s);
}
}
catch(Exception ex)
{
// ignore
}
}
}
Finally, the EJB That I was espected to lookup was found at:
"java:/openejb/local/FacadeBeanLocalBean", where FacadadeBean is the name of my EJB (stateless session bean).