Optimization of remote calls of EJB

Hello,
does the SAP Web AS support automatic optimization of remote calls of EJBs such that the overhead associated with remote calls is avoided iff the target EJB of the call actually runs in the same JVM (and therefore would allow a local call)? This would imply that in this case objects are passed by reference instead of by value.
To clarify: I am aware of the fact that EJBs can be called through Local and LocalHome interfaces. But that prevents the distribution of the EJBs. What I am looking for is to always use Remote and Home interface (remote call) and let the AppServer optimize the call to be virtually local if possible.
From what I know, JBoss and WebLogic support this feature. Is there anything like that for the Web AS. What do I need to configure?
Any hint is greatly appreciated. Please let me know if you need additional clarification on my question. Thanks!
With kindest regards,
Nick.

Hi Nick,
The optimizations I was talking about are a proprietary internal functionality and not something application developers can rely on. That's why they are not documented in any external documentation. According to your problem, my proposal is to declare both the remote and local interfaces of the beans and use the proper one depending on whether the bean client wants to pass parameters by value or by reference.
SAP does not have plans to dynamically (or automatically as you call it) switch from calling by value to calling by reference as this is not just a performance optimization - this breaks the functionality. If we decide to do it, we will have at least two problems:
1. Incompatibility with the RMI specification
2. Incompatibility with previous versions
As I already mentioned, there are EJB components that rely on being called by value, no matter whether the client resides in the same JVM or is a remote one.
I still cannot get your goal - both insisting on remote interfaces and expecting object-by-reference.
Best regards,
Viliana

Similar Messages

Does WLS 6.1 optimise remote calls?

Does WLS 6.1 optimise remote calls (remote method invocations) for EJBs that are
collocated on the same instance/same JNDI tree?
I've got a set of EJBs that I'd like to keep 'location independent' so I dont
want to use local interfaces. Will WLS do some magic under the covers to avoid
a remote network invocation (back to 127.0.0.1) when the EJBs are deployed together
in the same instance? Do I need to switch this feature on or is it done automatically?
Any help would be much appreciated.
Rich

"RajV" <[email protected]> wrote in message
news:[email protected]..
>
Hi Imeshev:
Is there any document on BEA's site that talks about the optimization?http://e-docs.bea.com/wls/docs70/ejb/reference.html#1070257
Regards,
Slava Imeshev
"Slava Imeshev" <[email protected]> wrote:
"Rich" <[email protected]> wrote in message
news:3e0742fd$[email protected]..
Does WLS 6.1 optimise remote calls (remote method invocations) forEJBs
that are
collocated on the same instance/same JNDI tree?
I've got a set of EJBs that I'd like to keep 'location independent'so I
dont
want to use local interfaces. Will WLS do some magic under the coversto
avoid
a remote network invocation (back to 127.0.0.1) when the EJBs are
deployed
together
in the same instance? Do I need to switch this feature on or is itdone
automatically?
weblogic performs local calls automatically for EJBs and their clients
residing in the same application (ejbjar or ear), or, to be more precise,
loaded by the same classloader.
Regards,
Slava Imeshev

How to call one EJB in another EJB?

How to call one EJB in another EJB? Please explain with some example code.

To refer a Ejb from another Ejb include <ejb-ref> element in ejb-jar.xml
<session>
<ejb-name>EjbA</ejb-name>
<ejb-ref>
<ejb-ref-name>EjbB</ejb-ref-name>
<ejb-ref-type>Entity</ejb-ref-type>
<home>com.ejb.EjbBHome</home>
<remote>com.ejb.EjbB</remote>
</ejb-ref>
</session>
Include a <reference-descriptor> in weblogic-ejb-jar.xml
<weblogic-enterprise-bean>
<ejb-name>EjbA</ejb-name>
<reference-descriptor>
<ejb-reference-description>
<ejb-ref-name>EjbB</ejb-ref-name>
<jndi-name>com.ejb.EjbBHome</jndi-name>
</ejb-reference-description>
</reference-descriptor>
</weblogic-enterprise-bean>
In EjbA Bean class refer to EjbB with
a remote reference to EjbB.
InitialContext initialContext=new InitialContext();
EjbBHome EjbBHome=(EjbBHome)
initialContext.lookup("com.ejb.EjbBHome");
EjbB ejbB=EjbBHome.findByPrimaryKey(primarykey);

How to Call one EJB from another

Hi all
I am trying to call one EJB in one system from another EJB residing on diferent system...
Both are Stateless session beans ...
I can't use No-args Intialcontext() as i need to specify the Ip address of other system to be looked up.....
So i am using properties Dorg.omg.CORBA.ORBInitlalHost....
But its not looking up..Its telling not bound...But i called it from standalone client remotely...
Am i wrong..?
I hope I am in right path....
I hope ill get reply as fast as possible...
Gopal V

Hi ken Thanks for replying....
Ya i packed it as a jar (using Export tool in Eclipse3.2)....
I am using SUN AS 9.....
I packed bean1 and bean2 as two different jars in the same domain...
Here is my code...
Bean1:
@Stateless(mappedName="ejb/Second")
public class SecondIMPL implements SecondRemote {
     public FirstRemote obj;
     public String connect() {
          try{
               InitialContext ctx= new InitialContext();
               FirstRemote obj =(FirstRemote)ctx.lookup("ejb/First");
               System.out.println("Client :"+obj.bMethod());
          }catch(Exception e){
               e.printStackTrace();
          return "Check server Log";
}Bean2 :
@Stateless(mappedName="ejb/First")
public class FirstIMPL implements FirstRemote {
     public String bMethod() {
          return "From First Bean";
Client:
public static void main(String[] args) {
          try{
               InitialContext ctx= new InitialContext();
               SecondRemote obj =(SecondRemote)ctx.lookup("ejb/Second");
               System.out.println("Client :"+obj.connect());
          }catch(Exception e){
               e.printStackTrace();
Here is my Stack Trace...
[#|2007-05-24T18:35:17.214+0530|WARNING|sun-appserver-pe9.0|javax.enterprise.system.stream.err|_ThreadID=18;_ThreadName=p: thread-pool-1; w: 19;_RequestID=bb4848e7-829a-421d-a560-93659898eb02;|
javax.naming.NamingException: ejb ref resolution error for remote business interfacecom.SecondRemote[Root exception is java.lang.ClassNotFoundException: com.SecondRemote]
     at com.sun.ejb.EJBUtils.lookupRemote30BusinessObject(EJBUtils.java:350)
     at com.sun.ejb.containers.RemoteBusinessObjectFactory.getObjectInstance(RemoteBusinessObjectFactory.java:61)
     at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:304)
     at com.sun.enterprise.naming.SerialContext.lookup(SerialContext.java:314)
     at javax.naming.InitialContext.lookup(InitialContext.java:351)
     at com.FirstBean.rediff(FirstBean.java:16)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     at java.lang.reflect.Method.invoke(Method.java:585)
     at com.sun.enterprise.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1050)
     at com.sun.enterprise.security.SecurityUtil.invoke(SecurityUtil.java:165)
     at com.sun.ejb.containers.BaseContainer.invokeTargetBeanMethod(BaseContainer.java:2766)
     at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:3847)
     at com.sun.ejb.containers.EJBObjectInvocationHandler.invoke(EJBObjectInvocationHandler.java:190)
     at com.sun.ejb.containers.EJBObjectInvocationHandlerDelegate.invoke(EJBObjectInvocationHandlerDelegate.java:110)
     at $Proxy36.rediff(Unknown Source)
     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     at java.lang.reflect.Method.invoke(Method.java:585)
     at com.sun.corba.ee.impl.presentation.rmi.ReflectiveTie._invoke(ReflectiveTie.java:121)
     at com.sun.corba.ee.impl.protocol.CorbaServerRequestDispatcherImpl.dispatchToServant(CorbaServerRequestDispatcherImpl.java:650)
     at com.sun.corba.ee.impl.protocol.CorbaServerRequestDispatcherImpl.dispatch(CorbaServerRequestDispatcherImpl.java:193)
     at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.handleRequestRequest(CorbaMessageMediatorImpl.java:1705)
     at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.handleRequest(CorbaMessageMediatorImpl.java:1565)
     at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.handleInput(CorbaMessageMediatorImpl.java:947)
     at com.sun.corba.ee.impl.protocol.giopmsgheaders.RequestMessage_1_2.callback(RequestMessage_1_2.java:178)
     at com.sun.corba.ee.impl.protocol.CorbaMessageMediatorImpl.handleRequest(CorbaMessageMediatorImpl.java:717)
     at com.sun.corba.ee.impl.transport.SocketOrChannelConnectionImpl.dispatch(SocketOrChannelConnectionImpl.java:473)
     at com.sun.corba.ee.impl.transport.SocketOrChannelConnectionImpl.doWork(SocketOrChannelConnectionImpl.java:1270)
     at com.sun.corba.ee.impl.orbutil.threadpool.ThreadPoolImpl$WorkerThread.run(ThreadPoolImpl.java:479)
Caused by: java.lang.ClassNotFoundException: com.Second
     at com.sun.enterprise.loader.EJBClassLoader.findClassData(EJBClassLoader.java:701)
     at com.sun.enterprise.loader.EJBClassLoader.findClass(EJBClassLoader.java:614)
     at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
     at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
     at com.sun.ejb.EJBUtils.getBusinessIntfClassLoader(EJBUtils.java:568)
     at com.sun.ejb.EJBUtils.lookupRemote30BusinessObject(EJBUtils.java:320)
     ... 31 more
|#]

Can I call an EJB from the database?

Hi,
I've just spent the last few days attempting to call an EJB from a stored procedure in a 10g database (and still haven't succeeded).
Now having spent hours searching the web (and this forum) for any successful examples (so far I have found none) I thought I'd add a message to see if there is anybody out there who has done this successfully. If so can you please provide me some details on how to do this?
Alternatively, I'd appreciate any input on how I can overcome my current hurdle in attempting to do this myself.
Here's how far I've got in my attempt:
I have a simple stateless session bean deployed to both Oracle 10gAS (a standalone OC4J container in 10.1.3) and to Weblogic 9. I have a client java class that calls a method on this bean and displays some ouput if successful. This all works from a standalone JVM (version 1.4) on both Weblogic and 10gAS.
I then tried to load the required libraries for Weblogic onto the database (namely the Weblogic.jar file). This resulted in the addition of some 32,000 odd objects of which 30,000 odd could not be resolved. I figured a lot of these may be down to JVM version issues (I believe that Weblogic 9 uses the 1.5 JRE) so I decided to put the Weblogic test on the back burner for now and just use the Oracle app server.
The tests with the Oracle app server looked promising. I only needed a handful of libraries to be loaded onto the database and all the relevant classes required for my test client had resolved (including the initial context factory required to do the jndi lookup of the bean). After granting all the permissions I believed I needed I'd got to the point where I could do a jndi lookup of the EJB; but when I tried to create an instance of the beans remote interface I got the following error:
java.security.AccessControlException: the Permission (java.lang.RuntimePermission getClassLoader) has not been granted to ProtectionDomain (file:generated/by/proxy <no certificates>)
com.evermind.net.DynamicClassLoader@612d9d34
<no principals>
java.security.Permissions@eb0f3c1a (
(java.util.PropertyPermission java.version read)
(java.util.PropertyPermission java.vm.name read)
(java.util.PropertyPermission java.vm.vendor read)
(java.util.PropertyPermission os.name read)
(java.util.PropertyPermission java.vendor.url read)
(java.util.PropertyPermission java.vm.specification.vendor read)
(java.util.PropertyPermission java.specification.vendor read)
(java.util.PropertyPermission os.version read)
(java.util.PropertyPermission java.specification.name read)
(java.util.PropertyPermission java.class.version read)
(java.util.PropertyPermission file.separator read)
(java.util.PropertyPermission java.vm.version read)
(java.util.PropertyPermission os.arch read)
(java.util.PropertyPermission java.vm.specification.name read)
(java.util.PropertyPermission java.vm.specification.version read)
(java.util.PropertyPermission java.specification.version read)
(java.util.PropertyPermission java.vendor read)
(java.util.PropertyPermission path.separator read)
(java.util.PropertyPermission line.separator read)
(java.net.SocketPermission localhost:1024- listen,resolve)
     at java.security.AccessControlContext.checkPermission(AccessControlContext.java:280)
     at java.security.AccessController.checkPermission(AccessController.java:429)
     at java.lang.SecurityManager.checkPermission(SecurityManager.java:528)
     at oracle.aurora.rdbms.SecurityManagerImpl.checkPermission(SecurityManagerImpl.java:192)
     at java.lang.Thread.getContextClassLoader(Thread.java:1203)
     at com.evermind.server.rmi.RMICall.<init>(RMICall.java:36)
     at com.evermind.server.rmi.RmiCallQueue.createCall(RmiCallQueue.java:33)
     at com.evermind.server.rmi.RMIClientConnection.createQueuedCall(RMIClientConnection.java:592)
     at com.evermind.server.rmi.RMIClientConnection.writeRequest(RMIClientConnection.java:581)
     at com.evermind.server.rmi.RMIClientConnection.sendMethodInvocationRequest(RMIClientConnection.java:426)
     at com.evermind.server.rmi.RMIClientConnection.invokeMethod(RMIClientConnection.java:415)
     at com.evermind.server.rmi.RemoteInvocationHandler.invoke(RemoteInvocationHandler.java:63)
     at com.evermind.server.rmi.RecoverableRemoteInvocationHandler.invoke(RecoverableRemoteInvocationHandler.java:28)
     at __Proxy0.create(Unknown Source)
     at com.axiomsystems.test.client.TestDBClient.test(TestDBClient.java:76)
Has anybody come across this before? If so can they help?
If not has anybody out there actually managed to call an EJB method (without going via an RMI server/Servlet/or any other proxy).
Any help in this matter would be greatfully appreciated.
Cheers,
Anand.

Sure, here's the code. It's what JDev generates automatically but I have seperated some things into several diffrent lines so I could experiment easier.
final Context context = getInitialContext();
Object o=context.lookup( "SessionEJB4" );
Object l= PortableRemoteObject.narrow( o, SessionEJB4Home.class );
final SessionEJB4Home sessionEJB4Home = (SessionEJB4Home)l;
SessionEJB4 sessionEJB4 = sessionEJB4Home.create();
String ret=( sessionEJB4.hello( ) );
As I mentioned, for this I have used EJB2.1 bean, because I had same problems with EJB3.0, so I tried earlier versions of Java to make sure that is not the problem.
hello() method just returns string "hello".
Of course, this works in standalone client that is not loaded into database.
Now, I loaded all the jars mentioned in this thread, using loadjava options -v -resolve, and I loaded client using options -v -resolve -genmissing . Select query on user objects in database shows that client class and relevant classes are all valid.
Then I created stub and ran it. First it stopped throwing exception ORA-29532: Java call terminated by uncought Java exception: Java.lang.NoClassDefFoundError.
Method I try to run returns String value which is hello message if it works fine, else it prints the part of the stack trace. In this case, after p[revious error, When I try to run it again, i get return from the method :
Lookup error: java.lang.NoClassDefFoundError; nested exception is:
     java.lang.NoClassDefFoundError
com.evermind.server.rmi.RMICall.throwRecordedException(RMICall.java:89)
com.evermind.server.rmi.RMIClientConnection.waitForJndiResponse(RMIClientConnection.java:371)
com.evermind.server.rmi.RMIClientConnection.lookup(RMIClientConnection.java:179)
com.evermind.server.rmi.RMIClient.lookup(RMIClient.java:283)
com.evermind.server.rmi.RMIClientContext.lookup(RMIClientContext.java:51)
javax.naming.InitialContext.lookup(InitialContext.java:347)
simpleejbproject.EJB4Client.hello(EJB4Client.java:35)
Of course, regular version of the client I run frokm command line works fine.
So I'm kind of a stuck here. I followed all directions, tried it on oracle 9 and oracle 10 DB, the problems remain the same. Am I missing something here?
Thanks
Just to add, getInitialContext()
    private static Context getInitialContext() throws NamingException {
        Hashtable env = new Hashtable();
        // Oracle Application Server 10g connection details
        env.put( Context.INITIAL_CONTEXT_FACTORY, "oracle.j2ee.rmi.RMIInitialContextFactory" );
        env.put( Context.SECURITY_PRINCIPAL, "oc4jadmin" );
        env.put( Context.SECURITY_CREDENTIALS, "manager1" );
        env.put(Context.PROVIDER_URL, "opmn:ormi://mserv:4005:home/TestEjb4");
        return new InitialContext( env );
It goes withouth any exceptions.
Message was edited by:
user510152

Calling an EJB throws an UNKNOWN exception

Hi EJB experts!
I`m trying to call an EJB on OAS from Java application running within a JDeveloper. After several calls of remote method the application invokes the remote method again but exception
java.rmi.UnexpectedException: CORBA: org.omg.CORBA.UNKNOWN: get a timeout exception; nested exception is:
org.omg.CORBA.UNKNOWN: get a timeout
is thown.
class Context {
public java.sql.Connection conn;
public EJBRemote logger;
Reference to a remote EJB is stored in class Context. Instance of Context is shared among three other objects. Strange thing is that whether the exception is thrown or not depends on the number of method calls on objects accessing the Context. In any case remote method completes successfuly. Do you have an idea what to do with this exception?
Thanks for any advice. David Mrva

http://www.jboss.org/online-manual/HTML/ch11s21.html

How to call the EJB methods from servlet/jsp

Hello ,
i have write one ejb signOn having the method validateUser(username,password).i can able to call this function from client.java class.i want to know whether i can call this function from servlet.if yes then where to write that servlet and web.xml file.
At present i m using weblogic server 8.1and i create directory call c:\ejb\demo and put the ejb files(home ,remote,ejb class ,client.java) then i have created .jar file and put in application file.
Now i want to create a servlet for that i have to create a new directory and put the servlet,web.xml,weblogin-web.xml file and then create one .war file and put in application directory or do some thing extra.Please help me.
Thanks In Advance
[email protected]

I think this might not be the most appropriate forum for your question. You might try a forum about ejb, or weblogic, or jndi.

Canu00B4t call an EJB from other EJB

Hi developers,
I need do the next task :
I have a EJB in an EAR and i need call some functionality from other EJB in diferent EAR , when execute the code show the next message error:
java.rmi.RemoteException: com.sap.engine.services.ejb.exceptions.BaseRemoteException: Exception in method generaMDMOutput.
     at com.sapconsulting.customer.inc.CustomerIncObjectImpl0.generaMDMOutput(CustomerIncObjectImpl0.java:135)
     at com.sapconsulting.customer.inc.CustomerIncObjectImpl0p4_Skel.dispatch(CustomerIncObjectImpl0p4_Skel.java:127)
     at com.sap.engine.services.rmi_p4.DispatchImpl._runInternal(DispatchImpl.java(Compiled Code))
     at com.sap.engine.services.rmi_p4.DispatchImpl._run(DispatchImpl.java(Inlined Compiled Code))
     at com.sap.engine.services.rmi_p4.server.P4SessionProcessor.request(P4SessionProcessor.java(Compiled Code))
     at com.sap.engine.core.service630.context.cluster.session.ApplicationSessionMessageListener.process(ApplicationSessionMessageListener.java(Compiled Code))
     at com.sap.engine.core.cluster.impl6.session.MessageRunner.run(MessageRunner.java(Compiled Code))
     at com.sap.engine.core.thread.impl3.ActionObject.run(ActionObject.java(Compiled Code))
     at java.security.AccessController.doPrivileged1(Native Method)
     at java.security.AccessController.doPrivileged(AccessController.java(Compiled Code))
     at com.sap.engine.core.thread.impl3.SingleThread.execute(SingleThread.java(Compiled Code))
     at com.sap.engine.core.thread.impl3.SingleThread.run(SingleThread.java(Compiled Code))
Caused by: java.lang.ClassCastException: com.sap.engine.interfaces.cross.ObjectReferenceImpl
     at com.sapconsulting.customer.inc.CustomerIncBean.generaMDMOutput(CustomerIncBean.java:141)
     at com.sapconsulting.customer.inc.CustomerIncObjectImpl0.generaMDMOutput(CustomerIncObjectImpl0.java:119)
     ... 11 more
the code to invoke the EJB is the next:
ctx = new InitialContext();
TestEJBLocalHome home = (TestEJBLocalHome) ctx.lookup("sap.com/TestEJB_ear/TestEJBBean");
               TestEJB servicio=(TestEJB)home.create();
the EJB are in the same server , please help,
regards

Hi Siarhei,
thank's for your answers , i'll explain the scenario , i think i copied wrong the code that i have ,
i have two EAR's applications , i want to call one EJB from the other EJB in other EAR , the call have to be remote , my code is the next :
ctx = new InitialContext();
Object obj = ctx.lookup("sap.com/TestEJB_ear/TestEJBBean");
TestEJBHome home = (TestEJBHome) PortableRemoteObject.narrow(obj,TestEJBHome.class);
TestEJB servicio= home.create();
i've confugured the ejb-xml.jar adding
<ejb-ref>
<ejb-ref-name>ejb/TestEJBBean</ejb-ref-name>
<ejb-ref-type>Session</ejb-ref-type>
<home>com.innovativesystems.onl.TestEJBHome</home>
<remote>com.innovativesystems.onl.TestEJB</remote>
</ejb-ref>
I've configured the ejb-j2ee-jar.xml adding
<ejb-ref>
<ejb-ref-name>ejb/TestEJBBean</ejb-ref-name>
<jndi-name>sap.com/TestEJB_ear/TestEJBBean</jndi-name>
</ejb-ref>
I've configured the application-j2ee-engine.xml adding a hard reference
<reference
reference-type="hard">
<reference-target
provider-name="sap.com"
target-type="application">TestEJB_ear</reference-target>
</reference>
with all this configuration still send me the message java.lang.classcast ,
something is missing???? ,
regards

Could not create remote for an EJB

Hello,
We have deployed an App on Sun One 7 that has web as well ejb modules integarted into it. The app deploys properly, However as soon as I try to call a servlet which in turn looks up an EJB (say ClientBean ) it gives me the followign error --->
"Could not create remote for Client Bean"
The entries in the xml files are as follows -
1) In ejb-jar.xml -
<session>
<ejb-name>EUClientBean</ejb-name>
<home>com..ejb.EUClientHomeIF</home>
<remote>com..ejb.EUClientRemoteIF</remote>
<ejb-class>com.ejb.EUClsClientBean</ejb-class>
<session-type>Stateless</session-type>
<transaction-type>Container</transaction-type>
<resource-ref>
<description>database ref</description>
<res-ref-name>test/db</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
</session>
2) in sun-ejb-jar.xml --
<ejb>
<ejb-name>EUClientBean</ejb-name>
<jndi-name>ejb/EUClientBean</jndi-name>
<ejb-ref>
<resource-ref>
<res-ref-name>test/db</res-ref-name>
<jndi-name>jdbc/test/db</jndi-name></resource-ref>
<pass-by-reference>true</pass-by-reference>
<bean-pool>
<pool-idle-timeout-in-seconds>0</pool-idle-timeout-in-seconds></bean-pool>
</ejb>
3) In sun-web.xml -
<ejb-ref>
<ejb-ref-name>ejb/test/client</ejb-ref-name>
<jndi-name>ejb/EUClientBean</jndi-name>
</ejb-ref>
4) In web.xml --
<ejb-ref>
<ejb-ref-name>ejb/test/client</ejb-ref-name>
<ejb-ref-type>Session</ejb-ref-type>
<home>com.ejb.EUClientHomeIF</home>
<remote>com.ejb.EUClientRemoteIF</remote>
<ejb-link>EUClientBean</ejb-link>
</ejb-ref>
Actually the same app was working on IAS 6.5.
Any ideas what cud have gone wrong?

Hi Mandar,
Can you post the exception you're getting in your servlet code? Does it happen when the servlet is looking up the ejb or when it tries to create it?
Regards,
Ken

Calling one EJB form another EJB

Hi,
i have 2 EJBs (Session Beans). Inside first EJB in one of its methods, i have to call the second EJB's one method. What are the steps invlovled in this operation?
Thanks

It's the same as calling an EJB from a client application. I'm not very good at it, but as much as I know, you need to lookup for the EJB Home object using JNDI and obtain the Remote object from it. Then you can call all the methods on the Remote object.
If the two EJBs reside in a different container, you would need to obtain a new InitialContext by passing the environment properties of the other container and then lookup as usual.
The only precaution you need to take is that you need the EJB-client JAR (containing the home and remote interfaces only) for the other EJB available so that ClassNotFoundException and similar exceptions are not thrown.
I hope I was helpful!
Regards,
UW

Error when One EJB calls anothe EJB

Hi,
I got the following error when I use one EJB call another EJB in OAS 4.0.8.1, the code is developed in JDeveloper 3.0/Win NT 4.0/SP5.
Can anyone give me some ideas? or is there any samples in this case?
Thanks a lot!
Creating an initial context
Looking for the EJB published as 'APP/APPEJB'
Creating a new EJB instance
Calling APPEJB methods...
CORBA: org.omg.CORBA.BAD_OPERATION: ; nested exception is:
org.omg.CORBA.BAD_OPERATION:
java.rmi.ServerException: CORBA: org.omg.CORBA.BAD_OPERATION: ; nested exception is:
org.omg.CORBA.BAD_OPERATION:
at javax.rmi.oas.corba.CorbaRemoteExceptionHelperValue.OBVObjFrom(Compiled Code)
at TwoEJB._stub_APPEJB.callEJBMapping(Compiled Code)
at TwoEJB.TwoEJBClient.main(Compiled Code)
null

Home handle is an object that identifies an enterprise bean. A client may serialize the handle, and then later deserialize it to obtain a reference to the enterprise bean.
The javax.ejb.HomeHandle is similar to javax.ejb.Handle. Just as the Handle is used to store and retrieve reference to EJB objects, the HomeHandle is used to store and retrieve remote references to EJB homes. HomeHandle can be stored and later used to access an EJB home remote refrence the same way that a Handle can be serialized and later used to access an EJB object's remoe reference.
import java.io.*;
import javax.ejb.EJBHome;
import javax.ejb.HomeHandle;
public class WorkingWithEJBHandles {
public static void main( String[] args ) throws Exception {
EJBHome aHome = null;
// get hold of a home interface
HomeHandle handle = aHome.getHomeHandle();
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutputStream oos = new ObjectOutputStream( bos );
oos.writeObject( handle );
byte[] handleAsBytes = bos.toByteArray();
// store in the database, on file. howwever you want
FileInputStream fis = new FileInputStream( "fileobj" );
ObjectInputStream ois = new ObjectInputStream( fis );
HomeHandle theHandle = (HomeHandle) ois.readObject();
// get back the EJBHome from the HomeHandle
aHome = theHandle.getEJBHome();
// the same kind of logic also holds for EJBHandles, as well as
// HomeHandles
Transfer Object is a Design pattern. Refer to Core J2EE Design Pattern.
http://java.sun.com/blueprints/corej2eepatterns/Patterns/TransferObject.html
Rgds,
Seetesh

How to access the Remote Appserver thru EJB

hi friends...
How to access the Remote appserver thru EJB from a Portlet.
I've tried but its not working u have any idea Plz help me out...
The scenario is I have my portal running in my machine & appserver(weblogic) running in remote and want to access that appserver
thru Remote EJB from my portal. I have tried with the t3 protocol and iiop but it is not working
The code i have use
Properties props = new Properties();
props.put(javax.naming.Context.INITIAL_CONTEXT_FACTORY,"weblogic.jndi.WLInitialContextFactory");
props.put(javax.naming.Context.PROVIDER_URL, "t3://10.1.87.46:7031");
it is giving me a nullpointer exception when i try to access the method in the ejb , it is not able to call that method...
Plz help me out to resolve this situation
Thnx in Advance.....

SanjayBala, just so you know that it is possible to create a database link in Oracle to non-Oracle databases in some circumstances. Look up Generic Connectivity aslo know as Heterogenous Services. With 11g Oracle has basically renamed the feature and replaced it with somethinkg named ike DG4ODBC.
I have not spent time studying the details for DB4ODBC but with HS Oracle provided the interface and you had to obtain the necessary ODBC driver on your own. I had Oracle on AIX reading and writing to SQL Server on Windows but the developers chose to write a java program and connect to both via it. On Windows and Linux platforms the necessary ODBC drivers might be available without the requirement to go out and purchase one.
The Oracle Open Gateway product is an advanced version of the above features with drivers for specific non-Oracle databases included like DB2 or Informix.
HTH -- Mark D Powell --

Calling an EJB from jsp - ServletException

I am unable to call an EJB from jsp, unless I put the actuall classes of
          the EJB into the classpath. Is this the right way to do it?
          The exception is:
          Servlet failed with ServletException
          javax.servlet.ServletException: Servlet class: 'jsp_servlet._result'
          could not be loaded - the requested class wasn't found in the
          classpath:
          '/local/apps/bea/wlserver6.0/config/gmodomain/applications/.wl_temp_do_not_delete/wl_local_comp34107.war:/local/apps/bea/wlserver6.0/./config/gmodomain/applications/.wl_temp_do_not_delete/WEB-INF/_tmp_war_gmo_gmo_webwar:/local/apps/bea/wlserver6.0/config/gmodomain/applications/.wl_temp_do_not_delete/WEB-INF/_tmp_war_gmo_gmo_webwar'
          at
          weblogic.servlet.internal.ServletStubImpl.prepareServlet(ServletStubImpl.java:532)
          at weblogic.servlet.jsp.JspStub.prepareServlet(JspStub.java:191)
          at weblogic.servlet.jsp.JspStub.prepareServlet(JspStub.java:148)
          at
          weblogic.servlet.internal.ServletStubImpl.getServlet(ServletStubImpl.java:306)
          at
          weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:208)
          at
          weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:246)
          at
          weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppServletContext.java:1265)
          at
          weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestImpl.java:1622)
          at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:137)
          at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120)
          where result.jsp is the jsp page calling the EJB. I did an import of the
          EJB classes in the jsp.
          like i said, it works if I put the bean classes in the classpath. But is
          it right?
          if I have these in the exploded format, do I need to put anything in the
          application web.xml under:
          wlserver6.0/config/gmodomain/applications/DefaultWebApp_gmo/WEB-INF ?
          redhat 6.2, wl6.0sp1
          here are the xml files:
          web.xml:
          <?xml version="1.0"?>
          <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application
          2.2//EN" "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">
          
          <web-app>
          <display-name>My Web Application</display-name>
          <description>none</description>
          <ejb-ref>
          <ejb-ref-name>MyWeb</ejb-ref-name>
          <ejb-ref-type>Session</ejb-ref-type>
          <home>com.blah.ejb.myweb.WyWebHome</home>
          <remote>com.blah.ejb.myweb.MyWeb</remote>
          </ejb-ref>
          </web-app>
          weblogic.xml:
          <!DOCTYPE weblogic-web-app PUBLIC "-//BEA Systems, Inc.//DTD Web
          Application 6.0//EN"
          "http://www.bea.com/servers/wls600/dtd/weblogic-web-jar.dtd">
          <weblogic-web-app>
          <jsp-descriptor>
          <jsp-param>
          <param-name>
          pageCheckSeconds
          </param-name>
          <param-value>
          1
          </param-value>
          </jsp-param>
          <jsp-param>
          <param-name>
          verbose
          </param-name>
          <param-value>
          true
          </param-value>
          </jsp-param>
          <jsp-param>
          <param-name>compileCommand</param-name>
          <param-value>/local/apps/jdk1.3.0_02/bin/javac</param-value>
          </jsp-param>
          </jsp-descriptor>
          <reference-descriptor>
          <ejb-reference-description>
          <ejb-ref-name>MyWeb</ejb-ref-name>
          <jndi-name>MyWeb</jndi-name>
          </ejb-reference-description>
          </reference-descriptor>
          </weblogic-web-app>
          thanks,
          Gary


Did you package your JSPs in a WAR and your EJBs in a JAR and package the
          WAR and JAR in an EAR? That is how to do it in 6.0. Works well.
          Peace,
          Cameron Purdy
          Tangosol, Inc.
          http://www.tangosol.com
          +1.617.623.5782
          WebLogic Consulting Available
          "gmo" <[email protected]> wrote in message
          news:[email protected]...
          > I am unable to call an EJB from jsp, unless I put the actuall classes of
          > the EJB into the classpath. Is this the right way to do it?
          > The exception is:
          > Servlet failed with ServletException
          > javax.servlet.ServletException: Servlet class: 'jsp_servlet._result'
          > could not be loaded - the requested class wasn't found in the
          > classpath:
          >
          '/local/apps/bea/wlserver6.0/config/gmodomain/applications/.wl_temp_do_not_d
          elete/wl_local_comp34107.war:/local/apps/bea/wlserver6.0/./config/gmodomain/
          applications/.wl_temp_do_not_delete/WEB-INF/_tmp_war_gmo_gmo_webwar:/local/a
          pps/bea/wlserver6.0/config/gmodomain/applications/.wl_temp_do_not_delete/WEB
          -INF/_tmp_war_gmo_gmo_webwar'
          >
          > at
          >
          weblogic.servlet.internal.ServletStubImpl.prepareServlet(ServletStubImpl.jav
          a:532)
          >
          > at weblogic.servlet.jsp.JspStub.prepareServlet(JspStub.java:191)
          >
          > at weblogic.servlet.jsp.JspStub.prepareServlet(JspStub.java:148)
          >
          > at
          >
          weblogic.servlet.internal.ServletStubImpl.getServlet(ServletStubImpl.java:30
          6)
          >
          > at
          >
          weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java
          :208)
          >
          > at
          >
          weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java
          :246)
          >
          > at
          >
          weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppServletCo
          ntext.java:1265)
          >
          > at
          >
          weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestImpl.java
          :1622)
          >
          > at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:137)
          >
          > at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120)
          >
          > where result.jsp is the jsp page calling the EJB. I did an import of the
          > EJB classes in the jsp.
          > like i said, it works if I put the bean classes in the classpath. But is
          > it right?
          > if I have these in the exploded format, do I need to put anything in the
          > application web.xml under:
          > wlserver6.0/config/gmodomain/applications/DefaultWebApp_gmo/WEB-INF ?
          >
          > redhat 6.2, wl6.0sp1
          >
          > here are the xml files:
          > web.xml:
          >
          > <?xml version="1.0"?>
          > <!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application
          > 2.2//EN" "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">
          >
          > 
          >
          > <web-app>
          > <display-name>My Web Application</display-name>
          > <description>none</description>
          > <ejb-ref>
          > <ejb-ref-name>MyWeb</ejb-ref-name>
          > <ejb-ref-type>Session</ejb-ref-type>
          > <home>com.blah.ejb.myweb.WyWebHome</home>
          > <remote>com.blah.ejb.myweb.MyWeb</remote>
          > </ejb-ref>
          > </web-app>
          >
          > weblogic.xml:
          >
          > <!DOCTYPE weblogic-web-app PUBLIC "-//BEA Systems, Inc.//DTD Web
          > Application 6.0//EN"
          > "http://www.bea.com/servers/wls600/dtd/weblogic-web-jar.dtd">
          > <weblogic-web-app>
          > <jsp-descriptor>
          > <jsp-param>
          > <param-name>
          > pageCheckSeconds
          > </param-name>
          > <param-value>
          > 1
          > </param-value>
          > </jsp-param>
          > <jsp-param>
          > <param-name>
          > verbose
          > </param-name>
          > <param-value>
          > true
          > </param-value>
          > </jsp-param>
          > <jsp-param>
          > <param-name>compileCommand</param-name>
          > <param-value>/local/apps/jdk1.3.0_02/bin/javac</param-value>
          > </jsp-param>
          > </jsp-descriptor>
          > <reference-descriptor>
          > <ejb-reference-description>
          > <ejb-ref-name>MyWeb</ejb-ref-name>
          > <jndi-name>MyWeb</jndi-name>
          > </ejb-reference-description>
          > </reference-descriptor>
          > </weblogic-web-app>
          >
          > thanks,
          >
          > Gary
          >
          >

Remote call exception

hi
I am using ejb 2 and I do a remote call
I need to pass the exception in the remote ejb to the local ejb
all what I see in my console is InvocationException , I need the real exception
how can I get it???
thanx

There is a getCause() method that you can use to get the cause of an exception. I hope that's what you were asking.

Trouble with deploying a standlone Java app/client that calls an EJB

Hey guys,
I am well aware that there are many topics that are quite similar to this topic that I am posting but the fact of the matter is I have failed to procure a satisfactory answer.
So a bit of background about the environment I am using. I am using Netbeans 5.5 development build, today's version, JDK 6 Build 77, and Sun Application Server 8.2 to create, run and learn J2EE 1.4 based apps following the Sun J2EE 1.4 tutorial pdf and the Netbeans 4.1 tutorial pdf which I realize is a bit outdated but it gets the job done for the most part.
I have satisfactorily created and built the Converter application as described in the above mentioned tutorial pdfs. For memory refreshment purposes, it is the simple session bean example where it is stateless and remote and has 2 business methods:
dollarToYen(BigDecimal dollar)
yenToEuro(BigDecimal yen)So I have this EJB being called, for learning purposes, by both a JSP and a Servlet as well as a standalone Java client. Now since the development machine is where I am deploying and running the enterprise application, everything works without a hitch. Once I have the Application server up and running I am able to access and execute the EJB's methods through JSP and Servlet even from remote machines on my home LAN. I realize that since the JSP and Servlet are in the same application context as that of the EJB I am not requiring the client jar which is where my confusion starts coming in. I know I need the client jar when I try to run the standalone java client from a different machine because it simply cannot access the EJB I have written.
Now I found this link below and I read it and sorta understand it. I also found that under C:\AppServer\domains\domain1\applications\j2eeapps\ConverterApp I see a file called ConverterAppClient.jar. Is this the so called client jar? If so how do I go about using it?
Before I end my rather long post, let me detail the steps I used to create the standlone Java client. I selected java application in the new menu of Netbeans and gave it the name ConverterClient and the IDE then proceeded to create a main class for me with a main method where I stuck in the following code:
try
            Context c = new InitialContext();
            Object remote = c.lookup("ejb/ConverterBean");
            ConverterRemoteHome rv = (ConverterRemoteHome) PortableRemoteObject.narrow(remote, ConverterRemoteHome.class);
            ConverterRemote converter = rv.create();
            BigDecimal param = new BigDecimal(100);
            System.out.println(param + " Dollars are " + converter.dollarToYen(param) + " Yen.");
            System.out.println(param + " Yen are " + converter.yenToEuro(param) + " Euro.");
        catch (RemoteException ex)
            ex.printStackTrace();
        catch (ClassCastException ex)
            ex.printStackTrace();
        catch (NamingException ex)
            ex.printStackTrace();
        catch (CreateException ex)
            ex.printStackTrace();
    }and that code works when I call it from the same machine that the Application Server is running with the EJB deployed. I also added in the classpath of the client application, the j2ee.jar and the other appserv-rt.jar as well. Have I missed anything?
I even tried using the deploytool but to no avail as all it generated for me was the same jar file that I found underneath the Application server application directory as I mentioned earlier.
If anyone is willing to help me, I will upload my Netbeans project files and all you have to do is open it through Netbeans 5.5 to recreate the exact scenario I am talking about.
Thanks in advance. I apologize for the rather long post but I thought it would be best to provide as much details as was possible.
Cheers,
Surya

hI,
Pls, I'm happy to know u r using application server. I have just started reading enterprise bean.
But I could not set the path and some other configurations for it to start working.
Pls, I would be most grateful, if u could put me through on how to configure application server.
Right now, I'm in the state of dilemma due to the insufficient knowledge in it.
My email is [email protected]
Remain blessed

Optimization of remote calls of EJB

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