NameNotFoundException on lookup in JSP

Question

I'm new to EJBs. I got an extremely basic stateless session bean to work on a JSP,
now I'm trying to get an entity bean working.
I'm getting a javax.naming.NameNotFoundException on my lookup. Here's my JSP code:
Hashtable ht = new Hashtable();
ht.put(Context.INITIAL_CONTEXT_FACTORY, "weblogic.jndi.WLInitialContextFactory");
ht.put(Context.PROVIDER_URL, "t3://localhost" );
Context ctx = new InitialContext( ht );
WBaseUserLocalHome userLocalHome = (VWBaseUserLocalHome) ctx.lookup("VWBaseUser");
(yes, I've changes my weblogic port from the default port 7001 to 80)
I thought that the string that you perform the lookup on is supposed to match
the <jndi-name> in the weblogic-ejb-jar.xml, and it is.

Answer 1

Inline.
Brian Preston wrote:
Excellent explanation, thanks. I think I followed most of it. Your explanation
also seems to describe my problem - I'm trying to deploy this test EJB as an 'exploded'
application, but I've only built the EJB with local interfaces. I previously
thought that since the JSP and EJB were running on the same server, the calls
would be local, not remote. I didn't know about the classloader issues.
So if I want to stick with the exploded app, I need to use Remote Interfaces then?Not necessarily. You could deploy the JSP in an exploded WAR format in the same exploded EAR
that contains the exploded JAR for the EJB. This deploys the JSP and the EJB in the same
classloader hierarchy allowing by reference semantics, therefore supporting the call to a Local
Interface fromt the JSP. Or, yes, you could just change the Local Interfaces to Remote
Interfaces. Really depends on the app, other apps, how you are using it, etc.
Bill
>
I'll go ahead and try both that, and packaging everything into a WAR and EAR.
I haven't tried that yet because I'm still trying to find explanation/documentation
about how to create those and what the directory structure is supposed to be before
you jar it.
Thanks,
Brian
William Kemp <[email protected]> wrote:
The EJB 2.0 Spec defines EJB Local Interfaces. The object that implements
these is not a
java.rmi.Remote object, and therefore may only be passed by reference.
When you refer to
them, you must be in the same JVM, and in the same enterprise app, on
WebLogic. They are
available and looked up through the local JNDI tree, which is common,
or local, to all of
the components in a J2EE app. An object reference may be returned when
looked up through the
local JNDI tree because the accessor and the object have been loaded
by the same classloader
hierarchy. You may not look them up and use them from outside of the
app because that
implies pass by value, which requires a java.rmi.Remote object.
So, if you access an EJB Local Interface, you must do it from the same
JVM and the same
enterprise application. As for examples, WLS is shipped with several
EJB 2.0 CMP examples
that demonstrate the use of Local Interfaces. In your example, you need
to package the JSP
and the EJB Local Inteface in the same EAR. Here are some good links
for this:
http://edocs.bea.com/wls/docs70/programming/index.html
http://edocs.bea.com/wls/docs70/programming/classloading.html#1029830
http://edocs.bea.com/wls/docs70/ejb/cmp.html#1070133
Bill
Brian Preston wrote:
Could you explain this a little more? I'm not following you when yousay 'access
to the local interfaces is scoped at the application level.' Somecode samples
would probably help, too. I'm pretty new to JNDI and RMI. I'm tryingto understand
these underlying APIs behind EJBs.
Thanks,
Brian
William Kemp <[email protected]> wrote:
The app can be exploded. The requirement is that access to the local
interfaces is scoped
at the application level.
Bill
Brian Preston wrote:
Thanks for your reply. Does that mean there's no way to do this
with
an 'exploded'
applicationk? I.e., without using an ear file?
William Kemp <[email protected]> wrote:
Looks like you are trying to look up a local interface in the global
jndi tree. Local
interfaces are only available in the local jndi tree. The JSP and
the
entity bean,
with the local interface you are trying to lookup, must be in thesame
J2EE
application which means they must be in the same application ear
file.
Bill
Brian Preston wrote:
I'm new to EJBs. I got an extremely basic stateless session bean
to
work on a JSP,
now I'm trying to get an entity bean working.
I'm getting a javax.naming.NameNotFoundException on my lookup.
Here's
my JSP code:
Hashtable ht = new Hashtable();
ht.put(Context.INITIAL_CONTEXT_FACTORY, "weblogic.jndi.WLInitialContextFactory");
ht.put(Context.PROVIDER_URL, "t3://localhost" );
Context ctx = new InitialContext( ht );
WBaseUserLocalHome userLocalHome = (VWBaseUserLocalHome) ctx.lookup("VWBaseUser");
(yes, I've changes my weblogic port from the default port 7001
to
80)
I thought that the string that you perform the lookup on is supposedto match
the <jndi-name> in the weblogic-ejb-jar.xml, and it is.