How do I reference an EJB inside anothe EJB ,both are on different hosts

Question

Hi,
I want to reference an EJB on one host inside another EJB in another
host. Even if i hardcode the url of the host on which the EJB is
deployed , it gives me the error regarding the no such ejb found.
I would appreciate your help.
Thanks

Answer 1

Robert,
We've been trying to implement this type of multi-server setup for some
time now. Our application consists of 260+ EJBs with a large team of
developers actively working against it. The business logic in our
application puts the EJBS in a highly interrelated situation. This
degree of interrelation makes it necessary for each developer to deploy
the entire application before any work can get done.
Starting a weblogic server, on a Windows Workstation, with 260+ beans is
very time consuming. But to get around this development bottle neck, we
are attempting the same scenario described in this thread. We have
recently upgraded from WL4.5.x to WL5.1 SP8. With WL5.1, we get the
CommunicationException seen previously in this thread. But the Error
message in WL5.1 is less descriptive. The 5.1 error message is missing:
WL6.0 Error Text: "This error could indicate that a component was
deployed on a cluster member but not other members of that cluster. Make
sure that any component deployed on a server that is part of a cluster
is also deployed on all other members"
It is obvious that weblogic's clustering depends on classes being
available to each server in the cluster, including the ejbc generated
_WLStub classes.  To me, it seems wrong that a weblogic server can only
use standard JNDI to lookup HomeInterfaces on other weblogic servers if
the hidden _WLStub classes are available to both servers.  I say this
because non-weblogic clients have JNDI lookup abilities without these
requirements. This whole experience was frustrating because all along
I knew that the solution was simply to take the hacker route and put the
classes in the the client classpath. I guess I just want to know if
this is bug? If not, I think it should be.
Thanks for listening
Steve Dodge
Steve Dodge
Realeum Inc.
Robert Patrick wrote:
Here is an example:
On server1, I have a Bean called TellerBean that calls the AccountBean
that lives on server2. To make this work, I need to deploy the
TellerBean.jar file AND any/all AccountBean Stub classes (any file in the
deployed version of the AccountBean.jar file matching the pattern
AccountBean*Stub.class) on server1. Server2 only needs to deploy the
AccountBean.jar file
Hope this helps,
Robert
kamps wrote:
Thanks.
I did include the files using import and they are alsso packaged
into the jar file .
I have done this , TradeCheck is the ejb i am trying to reference
in Trader EJB.
I package them into the jar file as follows:-
@REM Compile EJB classes into the build directory (jar preparation)
javac -d build TradeCheck.java TradeCheckHome.java Trader.java
TraderHome.java TraderBean.java TradeResult.java
@REM Make a EJB jar file, including XML deployment descriptors
cd build
jar cv0f std_ejb20_basic_statelessSession2.jar META-INF examples
images
cd ..
@REM Run EJBC on jar file
java -classpath
%WL_HOME%/lib/weblogic_sp.jar;%WL_HOME%/lib/weblogic.jar weblogic.ejbc
-compiler javac build\std_ejb20_basic_statelessSession2.jar
%APPLICATIONS%\ejb20_basic_statelessSession2.jar
It still gives the same error not finding the stub class.... Could
you kindly elaborate on what needs to be done.
I would appreciate your help.
Thanks,
Sunitha
Robert Patrick <[email protected]> wrote:
The problem is that the client that downloads the stubs
at runtime cannot
be another WebLogic Server. We do not support downloading
classes into a
running server so you will need to make sure that the
stubs are
"available" to the server that is acting as a client (e.g.,
packaged in
the EAR file) on the server acting as a client.
kamps wrote:
Thanks Mahendra. I am using WebLogic 6.0. Should I importthe package
in the first ejb which references the 2nd ejb or evenin the client
which references the first ejb.
Thanks again,
Sunitha
"Mahendra Dhamdhere" <[email protected]> wrote:
You are not getting the reference of stub.
try this. In your client program, import the package
in
which ejb classes
are present. As client downloads the stub from weblogic,
you have to import
the package where your stubs are present.
which version of weblogic are you using?
Mahendra
kamps <[email protected]> wrote in message
news:[email protected]...
Thanks,
I have 2 ejbs: one is TraderBean and a client RefClient.
TraderBean in turn calls a method of another bean
TradeCheckBean.
I tried making the changes as suggested but I amgetting
the following
error on the client side.
java examples.ejb20.basic.tatelessSession.RefClient"t3://localhost:7001"
javax.naming.CommunicationException. Root exceptionis
java.rmi.UnmarshalException:
failed to unmarshal class java.lang.Object; nested
exception
is:
java.lang.ClassNotFoundException:examples.ejb20.basic.statelessSession.Trade
CheckBeanHomeImpl_WLStub: This error could indicatethat a component
was deployed on
a cluster member but not other members of that
cluster.
Make
sure that any componen
t deployed on a server that is part of a cluster
is
also deployed
on all other member
s of that cluster
java.lang.ClassNotFoundException:examples.ejb20.basic.statelessSession.TradeCheckBea
nHomeImpl_WLStub: This error could indicate that
a
component was
deployed on a clus
ter member but not other members of that cluster.
Make
sure that
any component deploy
ed on a server that is part of a cluster is also
deployed
on all
other members of tha
t cluster
<<no stack trace available>>
I would appreciate any help.
Thanks,
kamps
"Mahendra Dhamdhere" <[email protected]> wrote:
you need to get initialcontext of that server.
Context ctx = null;
Hashtable ht = new Hashtable();
ht.put(Context.INITIAL_CONTEXT_FACTORY,
"weblogic.jndi.WLInitialContextFactory");
ht.put(Context.PROVIDER_URL, "t3://localhost:7001");
try
ctx = new InitialContext(ht); // Use
the
context
in your program
} catch (NamingException e)
{    // a failure occurred  }
finally {    try {ctx.close();}
catch (Exception e)
{      // a failure occurred    } }
use url of that other server. After getting initialcontext,
lookup for your
ejb.
Mahendra
kampu S <[email protected]> wrote in message
news:[email protected]...
Hi,
I want to reference an EJB on one host inside
another
EJB in another
host. Even if i hardcode the url of the host on
which
the EJB is
deployed , it gives me the error regarding the
no
such
ejb found.
I would appreciate your help.
Thanks