ClassNotFound while narrowing JNDI ref to ejb home interface

Hello everybody
I'm quite new to BEA WebLogic. I deployed Jasmine application on Bea WLS7 (example
app from Mastering EJB 2). But when i tried to use login servlet, it threw an
exception ClassNotFound when narrowing ejb home interface (obtained via JNDI).
EJBs are in .jar file, and web files are in the .war file, maybe this is the problem.
Should I copy ejb classes to .war file, or make some tricks with CLASSPATH, or
maybe there is better way to make it work (maybe via J2EE references or something
like this).
Thanks in advance

Strange. And you do not have any application classes in the system
classpath?
Konrad R. <[email protected]> wrote:
"Dimitri I. Rakitine" <[email protected]> wrote:
Did you deploy ejbs and war in the same ear?
Yes, both were packed up into one .ear archive>>
Konrad R. <[email protected]> wrote:
Hello everybody
I'm quite new to BEA WebLogic. I deployed Jasmine application on BeaWLS7 (example
app from Mastering EJB 2). But when i tried to use login servlet, itthrew an
exception ClassNotFound when narrowing ejb home interface (obtainedvia JNDI).
EJBs are in .jar file, and web files are in the .war file, maybe thisis the problem.
Should I copy ejb classes to .war file, or make some tricks with CLASSPATH,or
maybe there is better way to make it work (maybe via J2EE referencesor something
like this).
Thanks in advance--
Dimitri

Similar Messages

Unable to bind EJB Home Interface to the JNDI name

Why do I get this error?? What is the jndi-name in weblogic-ejb-jar.xml
Unable to deploy EJB: OrganizationEJB from sempire_bc.jar:
Unable to bind EJB Home Interface to the JNDI name:
com.sempire.builder.business
_component.Organization. The error was:
javax.naming.NameAlreadyBoundException: Organization is already bound;
remaining
name 'com.sempire.builder.business_component'
<<no stack trace available>>

Slava,
In case I change the name of the jndi name to a unique name. I still get the same
problem. I checked for multiple occurences, but there aren't any.
My web.xml file is:
<ejb-local-ref>
<description>
Reference EJB resources in Weblogic Resources
</description>
<ejb-ref-name>GangsterEJB</ejb-ref-name>
<ejb-ref-type>Entity</ejb-ref-type>
<local-home>com.sempire.builder.business_component.GangsterHome</local-home>
<local>com.sempire.builder.business_component.Gangster</local>
</ejb-local-ref>
My weblogic-ejb-jar.xml file is:
<weblogic-enterprise-bean>
<ejb-name>GangsterEJB</ejb-name>
<entity-descriptor>
<persistence>
<persistence-type>
<type-identifier>WebLogic_CMP_RDBMS</type-identifier>
<type-version>6.0</type-version>
<type-storage>META-INF/weblogic-cmp-rdbms-jar.xml</type-storage>
</persistence-type>
<persistence-use>
<type-identifier>WebLogic_CMP_RDBMS</type-identifier>
<type-version>6.0</type-version>
</persistence-use>
</persistence>
</entity-descriptor>
<reference-descriptor>
<resource-description>
<res-ref-name>jdbc/GangsterDB</res-ref-name>
<jndi-name>oraclePool</jndi-name>
</resource-description>
</reference-descriptor>
<local-jndi-name>Gangster_test</local-jndi-name>
</weblogic-enterprise-bean>
I do not get the problem.
Thank you
Ronak Parekh
"Slava Imeshev" <[email protected]> wrote:
Hi Ronak,
This exception means that you already have a bean
with the same JNDI name. Search your weblogic-ejb-jar.xml files
for multiple occurrences of the name and fix the problem.
Regards,
Slava Imeshev
"Ronak Parekh" <[email protected]> wrote in message
news:[email protected]...
Why do I get this error?? What is the jndi-name in weblogic-ejb-jar.xml
Unable to deploy EJB: OrganizationEJB from sempire_bc.jar:
Unable to bind EJB Home Interface to the JNDI name:
com.sempire.builder.business
_component.Organization. The error was:
javax.naming.NameAlreadyBoundException: Organization is already bound;
remaining
name 'com.sempire.builder.business_component'
<<no stack trace available>>

Casting error when trying to retrieve an EJB home interface from a servlet

          I am trying to call a method on a session bean from a servlet. I am receiving a Class Cast exception when trying to use the narrow method. I have this code working from an external java client. Is there something specific I have to do?


Hi
          You must check the following rules :
          1) In JAR Files ( of your EJB ) check if there are remote mehods that return
          any class that is already used in servlets
          This classes must be remove from the servlet package ( if you are using WAR
          files ).
          2) Please read the BEA WebLogic Enterprise Java Beans Manual about the class
          loader and related problemas such as ClassCastException and
          ClassNotFoundException.
          Good Luck !
          Steve Schaber <[email protected]> escribió en el mensaje de noticias
          39ee4996$[email protected]..
          >
          > I am trying to call a method on a session bean from a servlet. I am
          receiving a Class Cast exception when trying to use the narrow method. I
          have this code working from an external java client. Is there something
          specific I have to do?
          >

Problem in compiling ejb home interface

i am starting work on ejbs .the first thing i want to know is how to find an ejb api.I have searched the whole of java site but without success.
can anyone help me start on with ejbs.
Thank you.

there is book on the web, the author name is ed roman, it is free on the web, search in the search engine. www.google.com. this book will definitely help you
kiran

Undable to bind EJB Home during deploy

Hi
I'm getting an exception when I redeploy to weblogic81. I have and ear with several ejb jars in it. The following is the message I get...
Unable to bind EJB Home Interface to the JNDI name: EJBTestService. javax.naming.NameAlreadyBoundException: EJBTestService is already bound; remaining name :at weblogic.jndi.internal.BasicNamingNode.bindHere(BasicNamingNode.java:333) at weblogic.jndi.internal.ServerNamingNode.bindHere(ServerNamingNode.java:124) at weblogic.jndi.internal.BasicNamingNode.bind(BasicNamingNode.java:291) at weblogic.jndi.internal.WLEventContextImpl.bind(WLEventContextImpl.java:279) at weblogic.jndi.internal.WLContextImpl.bind(WLContextImpl.java:384) at weblogic.ejb20.deployer.ClientDrivenBeanInfoImpl.activate(ClientDrivenBeanInfoImpl.java:1116) at weblogic.ejb20.deployer.EJBDeployer.activate(EJBDeployer.java:1362) at weblogic.ejb20.deployer.EJBModule.activate(EJBModule.java:631)
This error doesn't always occur with the same jar in the ear. Sometimes the above jar prepares and activates fine and another one fails.
If anyone has any idea I'd appreciate feedback.

Hello,
The error suggests that an object is already bound to the JNDI name.
This can happen if you have 2 or more ejbs in your EAR file wit the same JNDI name or if your application has not fully/cleanly undeployed before you try to redeploy it.
I suspect the latter is your problem. Once you have undeployed your application use the weblogic console to view your JNDI tree and make sure nothing is bound that should not be bound. Then redeploy your app. If you still have the problem check your ear does not have duplicate ejbs or ejbs using the same JNDI name.

JNDI lookups of home interface

JNDI lookups are expensive timewise. Our question is ... would it be
pratical to lookup all our EJB Home interfaces once at startup and store
these references in a global class accessible to all clients? These home
interfaces then become readily available factories for acquiring instances
of remote interfaces. Is there anything wrong with this picture? Is this a
problem because these home stubs are not reentrant and may be accessed
concurrently by more than one client? Is there a problem with have one home
reference create multiple remote references of an ejb?
Any light that can be shed on this question wouls be appreciated.
Thanks.
tiffany
San Diego

I'm using a Singleton class to cache HomeInterfaces. The first time a
HomeInterface is requested, the JNDI lookup is done, after that, all
requests to that HomeInterface are handled by the cache. Works great, no
problems. AFAIK there are no problems with storing the HomeInterface
reference and reusing it.
Hope that helps,
Nils
Tiffany wrote:
>
JNDI lookups are expensive timewise. Our question is ... would it be
pratical to lookup all our EJB Home interfaces once at startup and store
these references in a global class accessible to all clients? These home
interfaces then become readily available factories for acquiring instances
of remote interfaces. Is there anything wrong with this picture? Is this a
problem because these home stubs are not reentrant and may be accessed
concurrently by more than one client? Is there a problem with have one home
reference create multiple remote references of an ejb?
Any light that can be shed on this question wouls be appreciated.
Thanks.
tiffany
San Diego--
============================
[email protected]

Could not lookup PortalManagerHome in the JNDI tree using EJB reference java:comp/env/ejb/PortalManager

Hi
I am just a starter on WLPortal.
I have created a barebone Application from scratch. I have synchronized it properly
from EBCC to WLP. But When I am trying to access the home page of my application,
I am getting from stack trace -
<Nov 6, 2002 5:37:59 PM IST> <Error> <PortalAppflow> <Could not lookup PortalManagerHome
in the JNDI tree using EJB reference java:comp/env/ejb/PortalManager.
javax.naming.NameNotFoundException: Unable to resolve comp/env/ejb/PortalManager
Resolved: 'comp/env' Unresolved:'ejb' ; remaining name 'PortalManager'
at weblogic.jndi.internal.BasicNamingNode.newNameNotFoundException(BasicNamingNode.java:802)
at weblogic.jndi.internal.BasicNamingNode.lookupHere(BasicNamingNode.java:209)
at weblogic.jndi.internal.BasicNamingNode.lookup(BasicNamingNode.java:173)
at weblogic.jndi.internal.BasicNamingNode.lookup(BasicNamingNode.java:181)
at weblogic.jndi.internal.BasicNamingNode.lookup(BasicNamingNode.java:181)
at weblogic.jndi.internal.WLContextImpl.lookup(WLContextImpl.java:323)
at weblogic.jndi.factories.java.ReadOnlyContextWrapper.lookup(ReadOnlyContextWrapper.java:36)
at weblogic.jndi.internal.AbstractURLContext.lookup(AbstractURLContext.java:124)
at javax.naming.InitialContext.lookup(InitialContext.java:350)
at com.bea.p13n.util.JndiHelper.lookupNarrow(JndiHelper.java:96)
at com.bea.portal.appflow.PortalAppflowHelper.<clinit>(PortalAppflowHelper.java:64)
at com.bea.portal.appflow.servlets.internal.PortalWebflowServlet.init(PortalWebflowServlet.java:78)
at javax.servlet.GenericServlet.init(GenericServlet.java:258)
at weblogic.servlet.internal.ServletStubImpl.createServlet(ServletStubImpl.java:700)
at weblogic.servlet.internal.ServletStubImpl.createInstances(ServletStubImpl.java:643)
at weblogic.servlet.internal.ServletStubImpl.prepareServlet(ServletStubImpl.java:588)
at weblogic.servlet.internal.ServletStubImpl.getServlet(ServletStubImpl.java:368)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:242)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:200)
at weblogic.servlet.internal.RequestDispatcherImpl.forward(RequestDispatcherImpl.java:215)
at weblogic.servlet.jsp.PageContextImpl.forward(PageContextImpl.java:112)
at jsp_servlet.__index._jspService(__index.java:92)
at weblogic.servlet.jsp.JspBase.service(JspBase.java:27)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:265)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:304)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:200)
at weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppServletContext.java:2459)
at weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestImpl.java:2039)
at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:139)
at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120)
>
<Nov 6, 2002 5:37:59 PM IST> <Error> <HTTP> <[WebAppServletContext(19695286,FirstWebApp,/FirstWebApp)]
Servlet failed with Exception
java.lang.NullPointerException:
at com.bea.portal.appflow.PortalAppflowHelper.createPortalManager(PortalAppflowHelper.java:82)
at com.bea.portal.appflow.servlets.internal.PortalWebflowServlet.setupPortalRequest(PortalWebflowServlet.java:187)
at com.bea.portal.appflow.servlets.internal.PortalWebflowServlet.doGet(PortalWebflowServlet.java:99)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:265)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:200)
at weblogic.servlet.internal.RequestDispatcherImpl.forward(RequestDispatcherImpl.java:215)
at weblogic.servlet.jsp.PageContextImpl.forward(PageContextImpl.java:112)
at jsp_servlet.__index._jspService(__index.java:92)
at weblogic.servlet.jsp.JspBase.service(JspBase.java:27)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:265)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:304)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:200)
at weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppServletContext.java:2459)
at weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestImpl.java:2039)
at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:139)
at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120)
When I decompiled the class PortalAppflowHelper, I found a static block in it,
which was as under-
static
debug = Debug.getInstance(com.bea.portal.appflow.PortalAppflowHelper.class);
try
if(debug.ON)
debug.out("Looking up PortalManagerHome using EJB reference java:comp/env/ejb/PortalManager");
portalManagerHome = (PortalManagerHome)JndiHelper.lookupNarrow("java:comp/env/ejb/PortalManager",
com.bea.portal.manager.ejb.PortalManagerHome.class);
if(debug.ON)
debug.out("Successfully retrieved PortalManagerHome " + portalManagerHome);
catch(Exception e)
PortalAppflowLogger.errorFindingPortalManagerHome("java:comp/env/ejb/PortalManager",
e);
I have checked the PortalManager's JNDI name on WLConsole. Its ${APPNAME}.BEA_portal.PortalManager.
Should I change it?
When I tried to change it, I started getting other weird errors.
Thanks
Neeraj Hans

Neeraj -
The Portal framework code (including PortalAppflowHelper) uses ejb
references to find the PortalManager (and other EJBs) from servlets and
taglibs; that is what is signified by the java:comp/env/... name.
Since you built your webapp from scratch (instead of using the portal
wizard), you will need to make sure the you have the appropriate
<ejb-ref> entries in your web.xml, and the corresponding
<ejb-reference-description> entries in your weblogic.xml. By default,
you will need at least mappings for:
- ejb/PortalManager
- ejb/UserManager
- ejb/GroupManager
- ejb/PipelineExecutor
- ejb/EventService
See either the resulting webapp from using the portal wizard or
BEA_HOME/weblogic700/samples/portal/sampleportalDomain/beaApps/sampleportal/sampleportal/WEB-INF
for example syntax.
Greg
Neeraj Hans wrote:
Hi
I am just a starter on WLPortal.
I have created a barebone Application from scratch. I have
synchronized it properly
from EBCC to WLP. But When I am trying to access the home page of my
application,
I am getting from stack trace -
<Nov 6, 2002 5:37:59 PM IST> <Error> <PortalAppflow> <Could not lookup
PortalManagerHome
in the JNDI tree using EJB reference java:comp/env/ejb/PortalManager.
javax.naming.NameNotFoundException: Unable to resolve
comp/env/ejb/PortalManager
Resolved: 'comp/env' Unresolved:'ejb' ; remaining name 'PortalManager'
at <stack trace lines snipped>
When I decompiled the class PortalAppflowHelper, I found a static
block in it,
which was as under-
static
debug =
Debug.getInstance(com.bea.portal.appflow.PortalAppflowHelper.class);
try
if(debug.ON)
debug.out("Looking up PortalManagerHome using EJB
reference java:comp/env/ejb/PortalManager");
portalManagerHome =
(PortalManagerHome)JndiHelper.lookupNarrow("java:comp/env/ejb/PortalManager",
com.bea.portal.manager.ejb.PortalManagerHome.class);
if(debug.ON)
debug.out("Successfully retrieved PortalManagerHome "
+ portalManagerHome);
catch(Exception e)
PortalAppflowLogger.errorFindingPortalManagerHome("java:comp/env/ejb/PortalManager",
e);
I have checked the PortalManager's JNDI name on WLConsole. Its
${APPNAME}.BEA_portal.PortalManager.
Should I change it?
When I tried to change it, I started getting other weird errors.
Thanks
Neeraj Hans

Problems while performing lookup for Local EJBs

Can anybody tell me how can i perform local ejb lookup in Sun app Server 8.0/8.1 ?
I have following entries in ejb-jar.xml.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE ejb-jar PUBLIC "-//Sun Microsystems, Inc.//DTD Enterprise JavaBeans 2.0//EN" "http://java.sun.com/dtd/ejb-jar_2_0.dtd">
<ejb-jar >
<enterprise-beans>
<session >
<ejb-name>TeamLeaderBean</ejb-name>
<local-home>spring.ejb.example.TeamLeaderLocalHome
</local- home>
<local>spring.ejb.example.TeamLeaderLocal</local>
<ejb-class>spring.ejb.example.TeamLeaderBean</ejb-class>
<session-type>Stateless</session-type>
<transaction-type>Container</transaction-type>
</session>
</enterprise-beans>
<assembly-descriptor></assembly-descriptor>
</ejb-jar>
In sun-ejb-jar.xml I have
<sun-ejb-jar>
<enterprise-beans>
<ejb>
<ejb-name>TeamLeaderBean</ejb-name>
<jndi-name>TeamLeaderBeanLocal</jndi-name>
</ejb>
</enterprise-beans>
</sun-ejb-jar>
In the client EJBs code I have used following ways of performing lookup...
ctx.lookup("java:comp/env//TeamLeaderBeanLocal");
ctx.lookup("java:comp/env/ejb/local/TeamLeaderBeanLocal");
ctx.lookup("ejb/TeamLeaderBeanLocal");
Unfortunately none of these performs a successful lookup...???
Can anybody solve my problem?

In order to look up a local EJB from an EJB client you have to add an <ejb-local-ref> element for client EJB. So:
<session>
<ejb-name>MyClientEJB</ejb-name>
<ejb-local-ref>
<ejb-ref-name>ejb/TeamLeaderBeanLocal</ejb-ref-name>
<ejb-ref-type>Session</ejb-ref-type>
<ejb-link>TeamLeaderBeanLocal</ejb-link>
</ejb-local-ref>
</session>
fil
Can anybody tell me how can i perform local ejb
lookup in Sun app Server 8.0/8.1 ?
I have following entries in ejb-jar.xml.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE ejb-jar PUBLIC "-//Sun Microsystems,
Inc.//DTD Enterprise JavaBeans 2.0//EN"
"http://java.sun.com/dtd/ejb-jar_2_0.dtd">
<ejb-jar >
<enterprise-beans>
<session >
<ejb-name>TeamLeaderBean</ejb-name>
<local-home>spring.ejb.example.TeamLeaderLocalHome
</local- home>
<local>spring.ejb.example.TeamLeaderLocal</local>
<ejb-class>spring.ejb.example.TeamLeaderBean</ejb-clas
s>
<session-type>Stateless</session-type>
<transaction-type>Container</transaction-type>
</session>
</enterprise-beans>
<assembly-descriptor></assembly-descriptor>
</ejb-jar>
In sun-ejb-jar.xml I have
<sun-ejb-jar>
<enterprise-beans>
<ejb>
<ejb-name>TeamLeaderBean</ejb-name>
<jndi-name>TeamLeaderBeanLocal</jndi-name>
</ejb>
</enterprise-beans>
</sun-ejb-jar>
In the client EJBs code I have used following ways of
performing lookup...
ctx.lookup("java:comp/env//TeamLeaderBeanLocal");
ctx.lookup("java:comp/env/ejb/local/TeamLeaderBeanLoca
l");
ctx.lookup("ejb/TeamLeaderBeanLocal");
Unfortunately none of these performs a successful
lookup...???
Can anybody solve my problem?

JAVA client JNDI lookup for EJB session in cluster in WLS 5.1

The documentation says :
          to obtain a Context for JNDI lookup do the following :
          Hashtable ht = new Hashtable();
          ht.put(Context.INITIAL_CONTEXT_FACTORY,
          "weblogic.jndi.WLInitialContextFactory");
          ht.put(Context.PROVIDER_URL, "t3://mycluster:7001");
          try {
          Context ctx = new InitialContext(ht);
          // Do the client's work
          catch (NamingException ne) {
          // A failure occurred
          finally {
          try {ctx.close();}
          catch (Exception e) {
          // a failure occurred
          where "mycluster" is the DNS name of my cluster. My DNS server (Windows 200
          DNS server) use round robin
          to call alernatively all the wls server node in "mycluster" and it's OK. The
          two servers of my cluster
          are called alternatively for my EJB session stateless.
          Now I unplug one of the two nodes of my cluster and the remaining server is
          called only 2 times
          and not after.
          Questions :
          -is the load balancing between the nodes of mycluster only rely on DNS or
          is there an internal
          mecanism in EJB sub to try one server then an other ?
          - do I need to obtain a new reference on JNDI Context for each call ?
          Thank's a lot.
          Farid Bellameche.


          I too have the same problem. My scenario is :
          I have the web tier architecture away from cluster. All ejbs are in cluster
          running in two seperate machines. We have a factory class running in
          webtier(we use servlet in this tier) which obtains home interface only once
          and stores it for future reference. When ever we need the remoteobject stub,
          we ask the factory class and which in turn uses the stored home interface to
          get the same.
          In the webtier, I list all the servers in the cluster as a part of url as
          mentioned by you.
          I started the web tier as well as Object tier cluster. I could see the
          request coming in both the machines in the cluster for the ejb. But When I
          bring one the server in the cluster,
          1. Web tier throws an exception saying that it could not connect
          to server using t3.
          2. The other machine which is running the server, also says
          'failed to create socket to : -32323234324 sever name
          using protocol t3.
          It looks like I am able to get load balance. But I am not able to get the
          fail over to be working.
          In the weblogic-ejb-jar.xml, I added the following.
          <clustering-descriptor>
          <home-is-clusterable>true</home-is-clusterable>
          <home-load-algorithm>round-robin</home-load-algorithm>
          </clustering-descriptor>
          I compiled and added the .jar file. So the jar file now has replica aware
          stubs.
          Could any one of you help me for why the fail over is not working?
          Suersh
          "Giri Alwar" <[email protected]> wrote in message
          news:[email protected]...
          > Farid,
          > (1) Yes, the stub has the logic to perform load-balancing and
          fail-over.
          > (2) In almost all cases, no. You can get the context once, store it
          and
          > use it thereafter. Please refer to
          > http://www.weblogic.com/docs51/cluster/concepts.html#1025061 for more
          info.
          >
          > A couple of notes on your situation. From what you are describing, your
          > Windows DNS server is setup to serve only one IP from the cluster (using
          > round-robin) as opposed to a list of all IP's in the cluster. Hence, the
          > initial context you obtain is tied to a single server in the cluster (the
          > one returned by the DNS). The weblogic implementation on the client side
          has
          > no idea of the existence of the other servers in the cluster. This is not
          a
          > cluster aware context. To obtain a cluster aware context, either list all
          > the IP's in the URL like t3://server1,server2,server3:7001 or have
          > "mycluster" return a list of all servers in the cluster.
          >
          > Giri
          >
          >
          > "Farid Bellameche" <[email protected]> wrote in message
          > news:[email protected]...
          > > The documentation says :
          > >
          > > to obtain a Context for JNDI lookup do the following :
          > > Hashtable ht = new Hashtable();
          > > ht.put(Context.INITIAL_CONTEXT_FACTORY,
          > > "weblogic.jndi.WLInitialContextFactory");
          > > ht.put(Context.PROVIDER_URL, "t3://mycluster:7001");
          > > try {
          > > Context ctx = new InitialContext(ht);
          > > // Do the client's work
          > > }
          > > catch (NamingException ne) {
          > > // A failure occurred
          > > }
          > > finally {
          > > try {ctx.close();}
          > > catch (Exception e) {
          > > // a failure occurred
          > > }
          > > }
          > >
          > > where "mycluster" is the DNS name of my cluster. My DNS server (Windows
          > 200
          > > DNS server) use round robin
          > > to call alernatively all the wls server node in "mycluster" and it's OK.
          > The
          > > two servers of my cluster
          > > are called alternatively for my EJB session stateless.
          > > Now I unplug one of the two nodes of my cluster and the remaining server
          > is
          > > called only 2 times
          > > and not after.
          > >
          > > Questions :
          > > -is the load balancing between the nodes of mycluster only rely on DNS
          > or
          > > is there an internal
          > > mecanism in EJB sub to try one server then an other ?
          > >
          > > - do I need to obtain a new reference on JNDI Context for each call ?
          > >
          > >
          > > Thank's a lot.
          > >
          > > Farid Bellameche.
          > >
          > >
          > >
          > >
          >
          >

Unable to lookup ejb local home interface after moving to wls 7.0

I'm getting an exception trying to lookup an ejb's local home interface
which I believe was deployed correctly. On startup I get the message:
EJB Deployed EJB with JNDI name
com.logistics.basedata.ejb.shipperspecificfveb.ShipperSpecificFVDOLocalHome.
However, when I try to do a lookup using this jndi name, I get the
following exception:
javax.naming.LinkException: . Root exception is
javax.naming.NameNotFoundException: Unable to resolve
'app/ejb/ShipperSpecificFVDO.jar#com.logistics.basedata.ejb.shipperspecificfveb/local-home'
Resolved: 'app/ejb'
Unresolved:'ShipperSpecificFVDO.jar#com.logistics.basedata.ejb.shipperspecificfveb'
; remaining name
'ShipperSpecificFVDO.jar#com.logistics.basedata.ejb.shipperspecificfveb/local-home'
The name it can't resolve is different than the name I was trying to
look up. I can see
com.logistics.basedata.ejb.shipperspecificfveb.ShipperSpecificFVDOLocalHome
in the jndi tree through the admin console, but the attributes Object
Class, Object Hash Code, and Object To String are blank.
This worked with weblogic 6.1 sp3. Is there something I missed in the
migration to 7.0?
Any help would be appreciated. Thanks in advance,
-Brad

That explains it - in 7.0 (unlike 6.1 - then the only factor was
classloaders arrangement) client has to be
in the same application (ear) - note JNDI links used to be able to lookup
local homes.
"Brad Geddes" <[email protected]> wrote in message
news:[email protected]...
I'm looking it up from a web application. I did notice a message on thistopic
from last thursday (subject: "Pls Help! Failed to access local Sessionbean in
7.0!"). In it, the individual said he had to add ejb-local-ref elementsin the
web.xml. I tried this but can't seem to get it to work.
javax.naming.NameNotFoundException: Unable to resolve ejb-link.
ShipperSpecificFVDO.jar#com.logistics.basedata.ejb.shipperspecificfveb isnot in
the context. The context includes the following link bindings: {} Makesure the
link reference is relative to the URI of the referencing module.
Also, I don't have a war or ear in the environment I'm working in; theejb's are
all deployed separately in jar files, and the web app is in explodedformat.
>
-Brad
"Dimitri I. Rakitine" wrote:
Are you looking up the local home from outside of an application ?
"Brad Geddes" <[email protected]> wrote in message
news:[email protected]...
I'm getting an exception trying to lookup an ejb's local home
interface
which I believe was deployed correctly. On startup I get the message:
EJB Deployed EJB with JNDI name
com.logistics.basedata.ejb.shipperspecificfveb.ShipperSpecificFVDOLocalHome.
>>>
However, when I try to do a lookup using this jndi name, I get the
following exception:
javax.naming.LinkException: . Root exception is
javax.naming.NameNotFoundException: Unable to resolve
'app/ejb/ShipperSpecificFVDO.jar#com.logistics.basedata.ejb.shipperspecificf
veb/local-home'
Resolved: 'app/ejb'
Unresolved:'ShipperSpecificFVDO.jar#com.logistics.basedata.ejb.shipperspecif
icfveb'
; remaining name
'ShipperSpecificFVDO.jar#com.logistics.basedata.ejb.shipperspecificfveb/loca
l-home'
The name it can't resolve is different than the name I was trying to
look up. I can see
com.logistics.basedata.ejb.shipperspecificfveb.ShipperSpecificFVDOLocalHome
in the jndi tree through the admin console, but the attributes Object
Class, Object Hash Code, and Object To String are blank.
This worked with weblogic 6.1 sp3. Is there something I missed in the
migration to 7.0?
Any help would be appreciated. Thanks in advance,
-Brad
Dimitri--
Dimitri

Unable to deploy EJB 3.0 on JBoss 4.0.4GA - no home interface

I am stuck in that my EJB3.0 project (one entity bean, one session bean and one client test bean) builds OK but somehow Eclipse Europa is unable to deploy it to JBoss (4.0.4 GA and 5 Beta) -- something to do with JNDI error as it involves javax.naming exceptions.
My Eclipse directory structure is :-
Titan (project name)
|
ejb - com.titan (package name)
| |
| domain -> Cabin.java (my entity bean)
| |
| travelagent -> TravelAgentBean.java
| -> TravelAgentRemote.java
|
META_INF -> ejb-jar.xml
-> MANIFEST.MF
-> persistence.xml
My ejb-jar.xml is :
<?xml version="1.0" encoding="UTF-8"?>
<ejb-jar id="ejb-jar_ID" version="2.1" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/ejb-jar_2_1.xsd">
<display-name>Titan</display-name>
<enterprise-beans>

<session >
<display-name>TravelAgentBean</display-name>
<ejb-name>com/titan/travelagent/ejb/TravelAgentBean</ejb-name>
<remote>com.titan.travelagent.ejb.TravelAgentRemote</remote>
<ejb-class>com.titan.travelagent.ejb.TravelAgentBean</ejb-class>
<session-type>Stateless</session-type>
<transaction-type>Container</transaction-type>
</session>
</enterprise-beans>
</ejb-jar>
And my persistence.xml is :
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
<persistence-unit name="Titan">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<class>com.titan.domain.Cabin</class>
<properties>
<property name="hibernate.connection.driver_class" value="oracle.jdbc.OracleDriver" />
<property name="hibernate.connection.url"
value="jdbc:oracle:thin:@localhost:1521:XE" />
<property name="hibernate.connection.username" value="SYSTEM" />
<property name="hibernate.connection.password" value="Swordfish1" />
</properties>
</persistence-unit>
</persistence>
I right-click on the Titan project name and choose Build Project. I get the following error message :-
13:01:06,046 WARN [verifier] EJB spec violation:
Bean : com/titan/travelagent/TravelAgentBean
Section: 7.11.2
Warning: A Session bean must implement, directly or indirectly, the javax.ejb.SessionBean interface.
13:01:06,046 WARN [verifier] EJB spec violation:
Bean : com/titan/travelagent/TravelAgentBean
Section: 7.11.3
Warning: A Session bean must define at least one ejbCreate method.
13:01:06,046 WARN [verifier] EJB spec violation:
Bean : com/titan/travelagent/TravelAgentBean
Section: 7.11.1
Warning: The session bean must implement either a remote home and remote, or a local home and a local interface or a service endpoint interface.
13:01:06,062 ERROR [MainDeployer] Could not create deployment: file:/C:/jboss-4.0.4.GA/server/default/deploy/Titan.jar
I don't understand, because as of EJB 3.0, you don't really need a home or local-home interface anymore...

Using @SecurityDomain("exemplo1") in my EJB and NOT providing jboss.xml, it works.
@SecurityDomain("exemplo1")
@RolesAllowed("yyy")
@Stateless(name="UserManagement")
public class UserManagementBean implements UserManagement {
public void add(User user) {
}Damn! This is some serious shit... I don�t want to configure this in every single EJB.
EJB 3.0 is nice, but some small trivial details like this and others, that was forgotten by Sun, piss me off!

Can l make an instance of EJB home handler / Datasource shared by EJB objs

all ejb guru
As far as l know, it is general rule of thumb to cache the EJB home handlers and datasource object at EJB bean instance. But can l go a step further, make the same instance of EJB home handlers and datasource object shared by more than 1 EJB bean instance ?
( l checked out the methods of javax.ejb.EJBhome and javax.sql.DataSource. They are not declared as synchronized. It seems to me that EJB home handlers and datasource object are not thread safe and not suitable for being shared. Even they are thread-safe, if they are shared by 1+ EJB bean instance. Sharing EJB home handlers and datasource object may interfere the thread management of EJB container. Am l correct ? )
It is highly appreciated someone can share with me your insight in this issue.
thanks & regards
Danny

Okay, you got me there. However, it's usually a better practice to start a new thread with your specific question instead of resurrecting old threads that (obviously) nobody cared enough to answer.
DataSources are retrieved from the container via JNDI. You may (generally) cache them in order to alleviate the JNDI lookup without worrying about Threads, as there is only (usually) one DataSource object per server (or node in a cluster). Do not cache (in your code) the Connection objects obtained from the DataSource - always close them in order to return them to the pool maintained by the DataSource.
Caching EJB HomeHandles is the accepted manner of avoiding repeated JNDI calls to locate EJBs. Typically, extracting the EJBHome from the HomeHandle re-initializes whatever network operations are embedded in the EJBHome object(s) by the vendor's implementation. Once again, you do not necessarily need to worry about Threads - the container and vendor implementation is already taking care of that for you, transparently.
Think about it: if there were Threading issues, even retrieving the above objects via JNDI would ensure that J2EE application servers wouldn't be Thread safe and all operations would be, essentially, blocked each time. Obviously, this is not the case since both DataSources and EJBHome objects can have multiple clients using them simultaneously. Just because there's not explicit synchronized tag on any of the methods defined in these interfaces doesn't mean they're single-Thread objects.

EJB home stubs in a cluster

The following URL describes how replica-aware EJB home stubs work. Basically,
when you do a lookup for the EJB home in JNDI, you get a home stub on any of the
nodes in the cluster.
However, I want to invoke EJBs on a particular node in the cluster. Can I do
this by simply disabling the replica-aware EJB home in the deployment descriptor
and doing a remote JNDI lookup on the desired node in the cluster? And if so,
would I have to bind each EJB's home to JNDI with a different name?
-reza
http://edocs.bea.com/wls/docs61/cluster/object.html#1006777
All bean homes can be clustered. When a bean is deployed on a server, its home
is bound into the cluster-wide naming service.
Because homes can be clustered, each server can bind an instance of the home under
the same name. When a client looks up this home, it gets a replica-aware stub
that has a reference to the home on each server that deployed the bean. When create()
or find() is called, the replica-aware stub routes the call to one of the replicas.
The home replica receives the find() results or creates an instance of the bean
on this server.

However, I want to invoke EJBs on a particular node in the cluster. Can Ido
this by simply disabling the replica-aware EJB home in the deploymentdescriptor
and doing a remote JNDI lookup on the desired node in the cluster? Andif so,
would I have to bind each EJB's home to JNDI with a different name?Yes. Something like that. We do that with JMS queues sometimes (to send a
message to a particular machine in the cluster).
Peace,
Cameron Purdy
Tangosol, Inc.
Clustering Weblogic? You're either using Coherence, or you should be!
Download a Tangosol Coherence eval today at http://www.tangosol.com/
"Behforooz" <[email protected]> wrote in message
news:3c8fc8bf$[email protected]..
>

EJB Home Objects and Stubs

Hi,
Can anyone pls tell me,what are the objects are created in Server after the Deployment of EJB.
Is the EJB Home Object,EJB Home Object Stub,EJB Home Object Skeleton, EJB Local Home Object, EJB LocalHome Object Stub,Ejb LocalHome Object Skeleton.And Finally both the Stub objects and Skeleton Objects will be stored in the Jndi Registry ?
Thanks in Advance,
Venkat

Nic,
Caching the home object is a comon practice.
Take a look here:
http://www.theserverside.com/resources/patterns_review.jsp
Look at the EJB Home Factory Pattern.
Regards,
-Dat

Why do we use a home interface in EJB

I am trying to figure out why we need to use a HOME Interface in every EJB that we deploy in a container ? What is the significance ?
Thanks

Some info:
A home interface defines the methods that allow a client to create, find, or remove an enterprise bean. The home interface is EJB's way of creating an object. Home interfaces act as factories to create session beans and entity beans. The home interface defines the bean's life cycle methods, One of two interfaces for an enterprise bean. The home interface defines zero or more methods for creating and removing an enterprise bean. For session beans, the home interface defines create and remove methods, while for entity beans, the home interface defines create, finder, and remove methods.
You may want to also look up:
http://java.sun.com/j2ee/learning/tutorial/
http://java.sun.com/developer/onlineTraining/J2EE/Intro2/j2ee.html

ClassNotFound while narrowing JNDI ref to ejb home interface

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