Need for idempotent stateless session beans

I'm trying to find a solution for failovering method calls on a stateless
          session bean, even for method calls that already have started.
          I understand that failover services for failures that occur while the method
          is in progress, are supported only for idempotent method.
          My question is why ???
          Assuming that I start a transaction each time I call a method on a bean, I
          believe that committing the work will be done only after the method returned
          successfully. Why can't the stub decide that if it something went wrong in
          the transaction then it wasn't committed and it can be run again ?
          We need the method call failover services real bad, while making the methods
          idempotent can be very awkward sometime.
          TIA
          Eran.

Eran Erlich wrote:
          > I'm trying to find a solution for failovering method calls on a stateless
          > session bean, even for method calls that already have started.
          > I understand that failover services for failures that occur while the method
          > is in progress, are supported only for idempotent method.
          > My question is why ???
          > Assuming that I start a transaction each time I call a method on a bean, I
          > believe that committing the work will be done only after the method returned
          > successfully. Why can't the stub decide that if it something went wrong in
          > the transaction then it wasn't committed and it can be run again ?
          Its hard to decide whether the stub has to retry or not since the failure
          could have happened anytime. So, the stub will retry only if it knows for sure
          that it is safe to retry.
          - Prasad
          >
          > We need the method call failover services real bad, while making the methods
          > idempotent can be very awkward sometime.
          >
          > TIA
          > Eran.

Similar Messages

Is it possible to restrict the object creation for stateless session beans

Hi,
Is it possible to restrict/fix the ejb object creation for stateless session beans in application server?
For example, i want to configure the application server ( am using JBOSS ) to create maximum of 10 session bean objects. and if any requests for the stateless session bean come, as application server has created 10 objects, the requests should be blocked.
Thanks in advance,
nvseenu

You can keep a counter in the application code. A static var won't work, but an entity and a consistent id should. This version would affect performance, but it would be portable to other app servers.
// ConstrainedBean.java
package unq.ejb;
import javax.ejb.Stateless;
import javax.ejb.CreateException;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.persistence.PersistenceContext;
import javax.persistence.EntityManager;
@Stateless
public class ConstrainedBean implements Constrained {
    final static int DEFAULT_COUNTERID = 1;
    @PersistenceContext EntityManager em;
    @PostConstruct
    protected void init() throws CreateException {
     ConstrainedBeanCounter counter =
         em.find(ConstrainedBeanCounter.class, DEFAULT_COUNTERID);
     if( counter == null ) {
         counter = new ConstrainedBeanCounter();
         counter.counterId = 1;
         counter.counterValue = 0;
         em.persist(counter);
     if( counter.atMaximum() ) {
         throw new CreateException("error attempting to create > 10 beans");
     else {
         counter.increment();
    @PreDestroy
    protected void destroy() {
     ConstrainedBeanCounter counter = em.find(ConstrainedBeanCounter.class,
                               DEFAULT_COUNTERID);
     counter.decrement();
    public void doSomething() { System.out.println("doSomething()"); }
// ConstrainedBeanCounter.java
package unq.ejb;
import javax.persistence.Entity;
import javax.persistence.Id;
@Entity
public class ConstrainedBeanCounter implements java.io.Serializable
    @Id public int counterId;
    public int counterValue = 0;
    public void increment() {
     counterValue++;
    public void decrement() {
     counterValue--;
    public boolean atMaximum() {
     return counterValue > 9;
}

Paradox - Should entity CMP EJB be faster than stateless session bean?

Please bear with me on this.
Just thinking of this scenario: hello world application. It can be implemented both as stateless session bean and entity bean.
There's no persistent. So for the entity bean, it will be container managed, and no code to do anything to the load/remove/create. - comparably the same as stateless bean.
Next, for the stateless session bean, each client call would require a dedicated instance of the EJB on the server (although for a very short amount of time). For the entity bean, it's shared, so only 1 instance is needed. It's also thread safe.
So, for a very high traffic, shouldn't the entity bean do better because of single instance?
What's other overhead?
Does the entity bean cost more connections than the stateless bean?

Feels like a comparison between apples and oranges.
A stateless session bean is like every other instance, so these can be pooled by the EJB container. The container is free to create an instance for each client if necessary. That's different.
A stateless session bean doesn't have to deal with a database that may or may not be located on another machine the way an entity bean does. There could be another network round trip involved. That's different.
Session and entity beans are intended for entirely different purposes. Just because you can write Hello World with both doesn't mean it's representative of what EJBs are used for. I don't think it's a good, meaninful comparison. JMO - MOD

Stateless session beans and idle timeouts (weblogic 10.3.1)

Need clarification about stateless session beans and the idle-timeout-seconds setting.
Situation is this – we have a process that is timing out due to an API call to a very slow Authentication server.
I am trying to resolve this with a code change, but need to further other understand what the server is actually doing.
We have a session bean which calls another which is calling a util class that does all the work and returns the results back up to the initial session bean. I have left out the ejbName in these examples (it’s irrelevant here).
Example:
SessionBean1 // basically called just once a day
@Session(defaultTransaction = Constants.TransactionAttribute.SUPPORTS,
enableCallByReference = Constants.Bool.TRUE,
type = Session.SessionType.STATELESS,
transTimeoutSeconds = "0",
initialBeansInFreePool = "0",
maxBeansInFreePool = "20")
Methods
@RemoteMethod() public boolean getUserList(String adminGroup) {
Map usrList = getUserList(adminGroup);
Private Map getUserList(String adminGroup) {
     return SessionBean2.getUsers(adminGroup);
SessonBean2
@Session(defaultTransaction = Constants.TransactionAttribute.SUPPORTS,
enableCallByReference = Constants.Bool.TRUE,
type = Session.SessionType.STATELESS,
transTimeoutSeconds = "0",
initialBeansInFreePool = "3",
maxBeansInFreePool = "20")
Method
@RemoteMethod() public Map getUsers(String adminGroup) throws RemoteException {
return javaUtilClass.getUsers(adminGroup);
JavaUtilClass
Method
public Map getUsers(String adminGroup) throws RemoteException {
     // This is where the work happens, calling the Authentication server to get a complete
     // list of users for an admin group. When the user list is around 1500 entries, this can
     // take an hour. Did I mention this server is very slow? It’s about this threshold of 1500
     // that causes the timeout.
     return Map of users
First thought, just bump the idle-timeout-seconds setting for the session beans (from the default 600), but that would be a temporary solution until the user list grew larger.
Second thought, refactor the call to the Authentication Server API to get the user list in blocks of data (say 400 at a time) and decreasing the call/response time between the method getUsers and the API call. This would still occur in the JavaUtilClass, so I am unsure this would make a difference. The session beans would still be idle and subject to timeout, correct?
Would setting initialBeansInFreePool to 1 in SessionBean1 make any difference?
Or should I be looking at replicating the re-factored method from the JavaUtilClass in SessionBean1 where the user list is being used so that the API calls come back to it and keep it 'active'?
Thanks for any advice you could give me on this.

Hi
regarding timeouts, there are two ways:
1.- Changing the settings in the JTA WebLogic domain , called "Timeout Seconds". This will affect globally to all EJB deployed in the domain.
or
2.- Specified directly in the bean with a weblogic annotation, like this:
@TransactionTimeoutSeconds(value = 300)I hope this will help you.
Regards.
Felipe

Call stateless session bean EJB 2.0 from Webdynpro Java UI

Hello,
Can someone please tell me asto how to call a stateless session bean EJB 2.0 from Webdynpro Java UI?
The NWDS version is 7.0.
Thanks and Regards,
Arya

Hi Aryadipta
Please check this pdfs
https://www.sdn.sap.com/irj/scn/index?rid=/library/uuid/b00917dc-ead4-2910-3ebb-b0a63e49ef10&overridelayout=true
Steps for calling stateless session bean in Webdynpro java
Go to NWDS -> open perspective ->j2ee
select EJB Module Project ->create a project with name
Open the Project -->RC on ejb-jar.xml -> Select new --> EJB
Give name to EJB Bean (First letter should be in capital letters)
select the type of bean as Stateless session bean and give the package name to store that EJB bean.
After that Expand ejb-jar.xml and then select the <projectEJB>
Double click on this on method tab double click you will get business method where we will create the methods for business logic
Double click on projectEJB and then RC on bean tab and write required business logic in bean window as follows(based on requirement we will design a business logic).
After writing the business logic go to project -> rebuild
Till now we have created one EJB jar file
then go to File-->Enterprise Application Project -->create a project (projectEAR)
After creating a project click on next-> here we will have ear projects and then we select specific project required for our application.(here select projectEJB)
After that Calculate EAR project will be available on j2ee explorer.
Right click on <Bean> here
select New->Web Service->give a name to webservice and select Default configuration type as simple SOAP
-->click next -> Finish.
That webservice and related are created in ejb-jar.xml .
Expand the ejb-jar.xml.and double click on < webservice>
RC ProjectEJB -> Build EJB Archive RC on CalculateEAR ->Build applicationarchive.
Expand the projectEAR->RC on CalculateEAR.ear->Deploy to J2EE Engine
Double click on calculateEAR.ear ->Webservice navigator tab ->we eill servers expand the node
select the specific WebService
Here we test the webservice by click on Test and test it.
After that go to Web dynpro perspective ->create one webdynpro Project and one component
RC on model> Select import Web Service model(last)>give model name and package
and select radio button as local file system or URL
Go to WSnavigator->copy the WSDL path and paste it in model WSDL path and click on finish.
from here onwards steps are same as that adaptive RFC model
Hope it helps
Thanks
Tulasi Palnati
Edited by: Tulasi Palnati on Aug 26, 2009 12:15 PM
Edited by: Tulasi Palnati on Aug 26, 2009 12:43 PM

Stateless Session Bean has no Context when called from WAR

Hello,
Here is the code for my stateless session bean (it will carry out certain actions based on the timer service)
package DigestTest;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.util.Date;
import javax.ejb.*;
import javax.ejb.TimedObject;
import javax.ejb.Timer;
* This is the bean class for the MasterTimerBean enterprise bean.
* Created Sep 7, 2006 9:05:09 AM
* @author ttaylor
public class MasterTimerBean implements SessionBean, MasterTimerRemoteBusiness, MasterTimerLocalBusiness, TimedObject
private SessionContext context;
public void setSessionContext(SessionContext aContext)
context = aContext;
* @see javax.ejb.SessionBean#ejbActivate()
public void ejbActivate()
* @see javax.ejb.SessionBean#ejbPassivate()
public void ejbPassivate()
* @see javax.ejb.SessionBean#ejbRemove()
public void ejbRemove()
// </editor-fold>
* See section 7.10.3 of the EJB 2.0 specification
* See section 7.11.3 of the EJB 2.1 specification
public void ejbCreate()
// TODO implement ejbCreate if necessary, acquire resources
// This method has access to the JNDI context so resource aquisition
// spanning all methods can be performed here such as home interfaces
// and data sources.
public void ejbTimeout(Timer timer)
try
BufferedWriter writer = new BufferedWriter(new FileWriter("C:\\timerTest.txt"));
writer.write("Timer has tripped");
writer.newLine();
writer.flush();
writer.close();
catch(Exception e)
return;
// Add business logic below. (Right-click in editor and choose
// "EJB Methods > Add Business Method" or "Web Service > Add Operation")
public String initializeTimer()
String result = "\n\nInitializing Timer\n";
try
// Create Your Timer
if(context!=null)
TimerService ts = context.getTimerService();
result = result+"Instantiating Timer Object\n";
Timer timer = ts.createTimer(new Date(), 5000, "TestTimer");
result = result+"About to grab TimerHandle";
TimerHandle timerHandle = timer.getHandle();
else
result = result+"\nContext Object is null\n";
catch (Exception e)
result = result+"\nError:\n"+e.toString();
return result;
public String writerTest()
String result = "about to write";
try
result = result+"\nOpening the file";
BufferedWriter writer = new BufferedWriter(new FileWriter("C:\\timerTest.txt"));
result = result+"\nWriter Test Passed";
writer.write("Writer Works");
writer.newLine();
result = result+"\nFlushing writer";
writer.flush();
result = result+"\nClosing writer";
writer.close();
catch (Exception e)
result = result+"\n"+e.toString();
return result;
I am calling initializeTimer() from a jsp page with a simple <jsp:useBean tag>.
The program keeps returning that the context variable is not set(this is from the context!=null conditional in initializeTimer()). I am very confused, I thought that setContext(...) was called by the container upon instantiation (and thus should happen completely without any action from me).
How am I able to call a session bean that has not had the context set?
Any information is appreciated,
Thanks,
Scott

thank you for your reply, rajeevm007.
it seems that the question is really a problem now.
i think i should update weblogic to the lastest version and confirm this question. if it still in there, it seems that we have to reset the global variables all manually. so, now, we are discussing that should we modify all the ejbs, or wait the next version of weblogic. :) of cause the second choice is a joke.
no other good choice?
maybe in the march of the next year....
cheers
thank you again.

A question about entity manager in stateless session bean.

JSR 220 ejbcore, page 47 : stateless session bean: All business object references of the same interface type for the same stateless session bean have the "same object identity", which is assigned by the container.
So, if we have two session beans in client code...
@EJB Cart cart1;
@EJB Cart cart2;
then cart1.equals(cart2)==true
If we declare entity manager in stateless session bean:
@PersistenceContext( unitName="ds" ,type=PersistenceContextType.TRANSACTION)
private EntityManager em;If cart1 and cart2 are the same reference, do we have any problem when using the same reference(maybe the same em? ) to get data from db?

If cart1 and cart2 are the same reference, do we have
any problem when using the same reference(maybe the
same em? ) to get data from db?No. In EJB, there is a distinction between the EJB reference and the bean instance.
Each time you make an invocation on an EJB reference for a stateless session bean,
the container can choose any instance of that bean's bean class to process the
invocation. That's true whether you invoke the same reference multiple times or
two difference references to the same bean.
Each bean instance is guaranteed to be single-threaded.

Would RollBacks For Stateless Session Beans work In case of Stored Procedures or Triggers Written in Oracle PL/SQl

          We are writing a J2EE application and using Weblogic 5.1 on Unix machine. We are
          considering writing some Stored Procedures or Triggers on Oracle DBMS. Hence our
          Stateless Session Beans / Data Access Objects (DAOs) would be calling those stored
          procedures, which would reside on Oracle 8.1.7 (on Windows 2000). (These Data
          Access Objects are running under the umbrella of a Stateless Session Beans). We
          are using WebLogic's Connection Pooling.
          Our question is: Would we get reliable rollbacks from our stored procedures. I
          mean would the Transaction Management process of the EJB container work. Remember
          the SQL is written in the Database (Oracle in this case) in the form of Stored
          Procedures / Triggers through PL/SQL.
          Any ideas or tips would help.


          I would agree with Cameron Purdy. Be very cautious to use Oracle specific
          Triggers / Stored Procedures. Consider following, (apart from what he said):
          1. Unreliable behaviour of the Oracle JDBC drivers, specially 8.1.6 family..
          (You may visit the Oracle's web site and see the newsgroups for the JDBC drivers).
          This is enough of a reason to stop right there.
          However for interest sake you may consider following issues:
          2. By use of Oracle specific Triggers / SPs the application will not be portable.
          Vendor Lock In. Remember your choice for J2EE compliant Server (WebLogic in this
          case). The whole purpose would be defeated by going for this option.
          3. There are issues related to the extensibility of the application. I have
          my reservations and would hold my breath on two phase commit protocol transactions
          being reliable in this scenario.
          Have fun...
          Terry
          "Cameron Purdy" <[email protected]> wrote:
          >Yes, the work performed by the SPs and the triggers would be in the same
          >tx.
          >
          >What would NOT work is if the data has been read into WebLogic and then
          >it
          >gets affected by a trigger or SP on the RDBMS, the data in WebLogic is
          >not
          >automatically re-read within that same tx so you need to be careful.
          >
          >Peace,
          >
          >--
          >Cameron Purdy
          >Tangosol Inc.
          >Tangosol Coherence: Clustered Coherent Cache for J2EE
          >Information at http://www.tangosol.com/
          >
          >
          >"Ahmad" <[email protected]> wrote in message
          >news:[email protected]...
          >>
          >> We are writing a J2EE application and using Weblogic 5.1 on Unix machine.
          >We are
          >> considering writing some Stored Procedures or Triggers on Oracle DBMS.
          >Hence our
          >> Stateless Session Beans / Data Access Objects (DAOs) would be calling
          >those stored
          >> procedures, which would reside on Oracle 8.1.7 (on Windows 2000). (These
          >Data
          >> Access Objects are running under the umbrella of a Stateless Session
          >Beans). We
          >> are using WebLogic's Connection Pooling.
          >> Our question is: Would we get reliable rollbacks from our stored
          >procedures. I
          >> mean would the Transaction Management process of the EJB container
          >work.
          >Remember
          >> the SQL is written in the Database (Oracle in this case) in the form
          >of
          >Stored
          >> Procedures / Triggers through PL/SQL.
          >> Any ideas or tips would help.
          >
          >

A tough one for EJB experts - Stateless session bean spec question

I am busy learning more about EJBs and came across something confusing regarding the legal operations in the various container callback methods for stateless session beans.
Specifically, the EJB spec states that in the ejbCreate() method, the SessionContext can be used to obtain a reference to the EJB Object. Now this makes perfect sense with stateful session beans, since the ejbCreate() method isn't called until a client is creating a bean and the container has linked that bean to the client's EJB Object. However, it is my understanding that when it comes to stateless session beans, the container creates the beans and adds them to the bean pool at its leisure. It is not until a business method is called by a client that a stateless bean is actually linked to an EJB object. So, how is it that a stateless bean could ever obtain a reference to an EJB Object from within ejbCreate(). Which EJB Object would it be linked to? This operation just doesn't appear to make sense in that context.
Can anyone clarify this for me?

Interesting question. I have such questions all the time! Here's a link to a similar discussion
http://saloon.javaranch.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic&f=70&t=000905
Also, I tried this using Weblogic 8.1. Tried to access the EJBObject in ejbCreate before any business method was invoked. I did this by specifying a value for initial-beans-in-free-pool and found that the hash code for the EJBObject was the same for all the bean instances that were created on startup.
I then invoked a business method and accessed the EJBObject in that method. Again the hash code for the object was the same as the one created on startup.
Seemed to be that there is a 1:n relation between the EJBObject and bean instances.
This may be container specific. The spec says the user should be able to invoke the getEJBObject() method in ejbCreate(), its upto the container to comply with it.

How to integrate hibernate with Stateless Session bean in weblogic10.0

Hi,
I need to invoke hibernate(3.x) DAO from EJB Stateless Session bean(EJB2.x). I am using mysql database. Can somebody please post the configuration.
Thanks in advance,
Rushi.

Hi Deepak,
Thanks for your reply.
Actually, our stand alone java application already using spring-hibernate feature. Now we are planning divide our application into modules and deploy each module as ejb beans. As it is already integrated with spring-hibernate we are not using entity beans as of now. My understanding is container uses some default transcation management .so, my question is what are all the configurations needs to be done to let weblogic 10.0 server uses org.springframework.orm.hibernate3.HibernateTransactionManager. I mean, is there are any .xml file in weblogic to configure all these? please reply deepak I am struck here..
Regards,
Rushi.

How to get stateful and stateless session bean in second jsp

I create stateful session bean in the first jsp, then how can I get the stateful session bean in the second jsp? I find that somebody store the bean in HttpSession.
If I store the stateful session bean in HttpSession, then I can get it in the second jsp. My problem is that I can store the stateless session bean in HttpSession, and get it in the second jsp. Then, both stateful and stateless can maintain the state in the second jsp. What is the difference between stateful and stateless session bean in this case ?
I understand the definition of stateful and stateless session bean, but I'm confuse how to use session bean. Can anyone provide sample jsp to show difference of stateful and stateless? How the stateful session bean can maintain the state for the client?

Greetings,
I create stateful session bean in the first jsp, then how can I get the stateful session bean in the
second jsp? I find that somebody store the bean in HttpSession.Which is the correct scope for sharing client-specific data when 'request' scope is insufficient.
If I store the stateful session bean in HttpSession, then I can get it in the second jsp. My problem is
that I can store the stateless session bean in HttpSession, and get it in the second jsp. Then, bothWhy is that a "problem"? Does your application not require the stateless bean to be shared? If so, then don't store the EJBObject reference in the session...
stateful and stateless can maintain the state in the second jsp. What is the difference betweenWhat do you mean by this exactly?..
stateful and stateless session bean in this case ?Statefulness of session beans is in regard to maintaining client state (er, in all cases). If your "stateless" bean is receiving information from the client (i.e. its caller) - either through a create method or a business method - and that information is available (retrievable from the bean) on subsequent method calls, then that bean is, in fact, stateful - regardless of how it is deployed.
I understand the definition of stateful and stateless session bean, but I'm confuse how to use
session bean.The correct question, it here seems, is "when" to use which type... Use a "stateful" bean when information about (from) the client (i.e. the caller) must be maintained across method calls of the bean. Use a "stateless" bean for general business methods that do not depend on "prior knowledge" of the client (i.e. the caller).
Can anyone provide sample jsp to show difference of stateful and stateless? How the statefulA "sample JSP" would yield nothing additional... The semantics of calling, using, and "persisting", bean references are always the same - regardless of type or class. However, the reason(s) for using one over the other depends entirely on the needs of your application.
session bean can maintain the state for the client?I recommend that you spend more time learning about EJBs generally. In particular, it seems you require more fundamental understanding of their scope and lifecycle. Refer to sections 4, 6, and 7 of the EJB 2.0 Specification.
Regards,
Tony "Vee Schade" Cook

Stateless Session Bean calling another Stateless Session Bean

Hi all,
I have written 2 Stateless Session bean and would like to call the business method of 2nd Stateless Session Bean in the business method of the 1st.
I have written the lookup code for 2nd SB in the business method of 1st SB and would like to execute the business method in the same method itself.
What do I have to do for the same for the following :
Deployment Descriptor file or any other file needs to be modified.
I am using Weblogic 6.1 and SQL Server 7.0 as database.
Thanks in advance,
Seetesh

This is actually quite similar to calling a session bean from anywhere.
Try this
//Session Bean 2 - Business Method, JNDI name SessionBean2
public void doSomethingMore(String what)
// Session Bean 1 which call.
public void doSomething()
   InitialContext initCtx = new InitialContext();
   SessionBean2Home home2 = null;
   SessionBean2 bean2 = null;
   try
     home2 = (SessionBean2Home)initCtx.lookup("SessionBean2");
     bean2 = home2.create();
   }catch(FinderException ex){..}
    catch(CreateExceptrion ex){..}
   try
     bean2.doSomethingMore("Anything");
   }catch(remoteException ex){..}
}In my case (webLogic 5.1) I did not need to change anything in any of the deployment descriptor. However, both beans needs top be deployed on same instance of Application server (might work across instances but didnt try)
This should do it.
Amitabh

Stateless Session Bean + EJB Question + Jboss

Hello,
If I have a stateless session bean on a linux machine and it works locally what do i need to do to access a method in the session bean from a remote windows machine.
I would like to be able to execute my client jar file on a windows machine and have it access the jboss server on the linux machine. what do i need to do?
i have the session bean working locally on both windows and linux machine. do i need to to have a JSP/Servlet to access the session bean? can the session bean not be accessed directly? what should my classpath look like? do I need to include extra jar files in my client jar file.?
Thanks,
Joyce

Thanks guys for the help but I am still a little lost.
My Client windows machine has the client jar file and all the other jar files. This is my client class
package helloworld.client;
import javax.naming.Context;
import javax.naming.InitialContext;
import java.util.Hashtable;
import java.util.Properties;
import helloworld.interfaces.HelloWorldHome;
import helloworld.interfaces.HelloWorld;
public class HelloClient
     public static void main(String[] args)
          Hashtable prop = new Hashtable();
          prop.put ("java.naming.factory.url.pkgs","org.jboss.naming:org.jnp.interfaces");
          prop.put ("java.naming.provider.url","jnp://172.16.220.160:1099");
          prop.put ("java.naming.factory.initial","org.jnp.interfaces.NamingContextFactory");
          try
               Context ctx = new InitialContext(prop);
               Object obj = ctx.lookup("ejb/helloworld/HelloWorld");
               System.out.println(obj);
               HelloWorldHome home = (HelloWorldHome)javax.rmi.PortableRemoteObject.narrow(obj, HelloWorldHome.class);
               HelloWorld helloWorld = home.create();
               String str = helloWorld.sayHelloEJB("JOYCE is COOL");
               System.out.println(str);
               helloWorld.remove();
          catch(Exception e)
               e.printStackTrace();
I get a NullPointer ie the home object is null. The IP address is the IP of the Linux machine that has Jboss running on.
Questions are:
1. Do I need to have Tomcat running on my client machine if I am to connect via HTTP? Does this alter my client code.?
2. My JNDI lookup is what is causing the problem. Does my jboss.xml and my ejb-jar.jar look okay to you.
jboss.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE jboss PUBLIC "-//JBoss//DTD JBOSS//EN" "http://www.jboss.org/j2ee/dtd/jboss.dtd">
<jboss>
<enterprise-beans>
<session>
<ejb-name>helloworld/HelloWorld</ejb-name>
<jndi-name>ejb/helloworld/HelloWorld</jndi-name>
</session>
</enterprise-beans>
<resource-managers>
</resource-managers>
</jboss>
ejb-jar.jar
<?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 >
<description>No Description.</description>
<display-name>Generated by XDoclet</display-name>
<enterprise-beans>

<session >
<description><![CDATA[No Description.]]></description>
<ejb-name>helloworld/HelloWorld</ejb-name>
<home>helloworld.interfaces.HelloWorldHome</home>
<remote>helloworld.interfaces.HelloWorld</remote>
<ejb-class>helloworld.session.HelloWorldBean</ejb-class>
<session-type>Stateless</session-type>
<transaction-type>Bean</transaction-type>
</session>





</enterprise-beans>


<assembly-descriptor >



</assembly-descriptor>
</ejb-jar>
Do I need RMI ? Do I need to concern myself with CORBA? All Im looking for is a step by step to understanding what I need to configure? Is their some way I can debug?
Thanks alot,
Joyce

Stateless session Bean - xml and ejb-jar.xml file ???

Dear Experts,
Stateless-session bean
For Creating an ear file
we need ejb-jar.xml and weblogic-ejb-jar.xml files
Is these files are already available
or we have to type these files ??
Advance Thanks
Rengaraj.R

My best advice: surrender to use an IDE.
You wonder sometimes at how much productivity (read as 'time') could be wasted by doing something that could be done automatically. For a learning experience or a once only exercise is fine but as a routine thing, not worth it.
Cheers

Not be able to obtain a transacted session within stateless session bean

I need some assistance on creating a transacted session. For some reason while within a stateless session bean, I am unable to create a transacted session even though I'm specifying to create the transacted queue session. Can anyone provide any assistance to me on this? It would be much appreciated.
Here is the code snippets involved with the problem:
Code snipet from ejb-jar.xml:
<session>
<display-name>Initial Request</display-name>
<ejb-name>InitialRequestBean</ejb-name>
<ejb-class>com.raytheon.rds.jms.InitialRequestBean</ejb-class>
<session-type>Stateless</session-type>
<transaction-type>Container</transaction-type>
</session>
Code from stateless session bean:
static Logger logger;
private QueueConnectionFactory connectionFactory;
private SessionContext sc;
private Queue requestQueue;
public String processRequest(String msgBody)
logger.log(Level.INFO, "In processRequest(String).", msgBody);
QueueConnection con = null;
QueueSession session = null;
QueueSender sender = null;
TextMessage message = null;
String messageID = null;
QueueReceiver receiver = null;
TemporaryQueue replyQueue = null;
boolean transacted = false;
try
//Create the infrastructure (ie. The connection & the session)
logger.log(Level.FINE, "Creating connection");
con = connectionFactory.createQueueConnection();
logger.log(Level.FINE, "Creating session");
session = con.createQueueSession(true, Session.AUTO_ACKNOWLEDGE);
//Note: This line above was changed in all possible permutation and still didn't work such as using Session.SESSION_TRANSACTED
transacted = session.getTransacted();
logger.log(Level.FINE, "Is session transacted? : " + transacted);
//Note: This line above is constantly saying false
//Now first, setup the temporary reply queue and its listener
replyQueue = session.createTemporaryQueue();
logger.log(Level.FINE, "Creating receiver/consumer");
receiver = session.createReceiver(replyQueue);
con.start();
//Now create the requestor that will make the request message and put it on the request queue
logger.log(Level.FINE, "Creating Requestor/Producer");
sender = session.createSender(requestQueue);
//Now create the message and make sure that you put the "JMSReplyTo" property to the temporary response queue we just created
message = session.createTextMessage();
message.setJMSReplyTo(replyQueue);
logger.log(Level.FINE, "Created message: " + message.getJMSMessageID());
//Now add the actual info you want to send
message.setText(msgBody);
//Now send the message
logger.log(Level.INFO, "Sending message: " + message.getText());
sender.send(message);
//Now wait until we get a response
logger.log(Level.FINE, "Waiting for the response message");
Message responseMsg = receiver.receive(20000); //Toggle the "0" to specify timeout in millisectionds
//Process the message
logger.log(Level.FINE, "Processing the response message");
if(null != responseMsg)
logger.log(Level.FINE, "responseMsg is : " + responseMsg.toString());
messageID = processMessage(responseMsg);
logger.log(Level.FINE, "Response is : " + messageID);
//close the connection
logger.log(Level.FINE, "Stopping the connection");
con.stop();
catch (Throwable t)
// JMSException could be thrown
logger.log(Level.SEVERE, "Exception Thrown in sendRequest: ", t);
sc.setRollbackOnly();
finally
//Close the sender
if (sender != null)
try
logger.log(Level.FINE, "Closing the sender");
sender.close();
catch (JMSException e)
logger.log(Level.WARNING, "JMSException Thrown when trying to close the sender to the request queue: ", e);
else
logger.log(Level.FINE, "Sender is already closed.");
//Close the receiver
if (receiver != null)
try
logger.log(Level.FINE, "Closing the receiver");
receiver.close();
catch (JMSException e)
logger.log(Level.WARNING, "JMSException Thrown when trying to close the receiver to the request queue: ", e);
else
logger.log(Level.FINE, "Receiver is already closed.");
//Close the session
if (session != null)
try
logger.log(Level.FINE, "Closing the session");
session.close();
catch (JMSException e)
logger.log(Level.WARNING, "JMSException Thrown when trying to close the session to the request queue: ", e);
else
logger.log(Level.FINE, "Session is already closed.");
//Close the connection
if (con != null)
try
logger.log(Level.FINE, "Closing the connection");
con.close();
catch (JMSException e)
logger.log(Level.WARNING, "JMSException Thrown when trying to close the connection to the reply queue: ", e);
else
logger.log(Level.FINE, "Connection is already closed.");
return messageID;
}

I found the answer through lots of painful searching.
http://blogs.sun.com/fkieviet/entry/request_reply_from_an_ejb
This weblog from Frank Kieviet from a sun blog explains what's happening behind the scenes.
Then I proceeded to create a Bean-Managed Transaction out of my EJB, which is using EJB 3.0. This requires the tag:
@TransactionManagement(value= TransactionManagementType.BEAN)
Note: I got this information from http://download.oracle.com/docs/cd/B31017_01/web.1013/b28221/servtran001.htm#BAJIBAFF
Then I just added the code specified in Frank's blog and everything is working now. The main portion of the code looks like this now:
//begin the user transaction
ctx.getUserTransaction().begin();
//Create the infrastructure (ie. The connection & the session)
logger.log(Level.FINE, "Creating connection");
con = connectionFactory.createQueueConnection();
//Create the session
logger.log(Level.FINE, "Creating session");
session = con.createQueueSession(false, Session.SESSION_TRANSACTED);
transacted = session.getTransacted();
logger.log(Level.FINE, "Is session transacted? : " + transacted);
//Now create the sender that will make the request message and put it on the request queue
logger.log(Level.FINE, "Creating Sender");
sender = session.createSender(requestQueue);
//Now create the message
message = session.createTextMessage();
//Now add the actual info you want to send
message.setText(msgBody);
logger.log(Level.FINE, "Created message: " + message.getJMSMessageID());
//Now first, setup the temporary reply queue and its listener
replyQueue = session.createTemporaryQueue();
if(null != replyQueue)
logger.log(Level.FINE, "Created temporary queue: " + replyQueue.getQueueName());
else
logger.log(Level.FINE, "Temporary Queue could not be created.");
//make sure that you put the "JMSReplyTo" property to the temporary response queue we just created
message.setJMSReplyTo(replyQueue);
//Now send the message
logger.log(Level.INFO, "Sending message: " + message.getText());
sender.send(message);
//Now start the connection
logger.log(Level.FINE, "Starting the connection");
con.start();
//commit the changes
ctx.getUserTransaction().commit();
ctx.getUserTransaction().begin();
//Create the receiver
logger.log(Level.FINE, "Creating Receiver");
receiver = session.createReceiver(replyQueue);
//Now wait until we get a response
logger.log(Level.FINE, "Waiting for the response message");
Message responseMsg = receiver.receive(20000); //Toggle the "0" to specify timeout in millisectionds
//Process the message
logger.log(Level.FINE, "Processing the response message");
if(null != responseMsg)
logger.log(Level.FINE, "responseMsg is : " + responseMsg.toString());
else
logger.log(Level.FINE, "No response came back.");
messageID = processMessage(responseMsg);
logger.log(Level.FINE, "Response is : " + messageID);
logger.log(Level.FINE, "Transaction is complete");
//commit the changes
ctx.getUserTransaction().commit();

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