Transaction management in BMP through Session bean(worked in J2EE RI)

This thing worked in the J2EE RI implementation, but not in OC4J.
Problem is:
In a BMP, if we throw an EJBException all the changes would be rolled back by the container, right? Or do we have to write code to do that?
I was reading through your reply in the list and I have a doubt regarding something regarding transaction handling in BMP entity beans. I am using the entity bean in a session bean and have two sql statements and one entity update. If one of the sql statements fails and the entity is updated , the changes are all rolled back, but in the case of the entity failure to update, the sql statement changes are not rolled back and I get an error saying
System/communication error: Transaction was rolled back: Error preparing bean in
stance: com.evermind.transaction.MarshallingXAException; nested exception is:
com.evermind.transaction.MarshallingXAException
The entity bean is throwing an EJBException back to the Session bean, but the session bean does not catch
it and continues forward as if nothing happened.
The funny thing is that the queries are placed like this
sqlinsert 1.......
entitybean update....
sqlinsert 2.....
So the flow becomes
sqlinsert 1 happens then sqlinsert 2 and only in the end does the entity bean throw the exception
any idea why this happens?
Can anyone help me on this. The BMP entity has persistence
<persistence-type>Bean</persistence-type>
Thanks
Kind Regards
Aby Philip

Hi,
In general, whenever you manage your own transactions (such as in DAOs or in stored procedures) then you are limiting the ways that your code can be reused: your code will never be able to run in a client's transaction. This could mean trouble if you want to combine you software inside other beans that use it: when these other beans lead to a rollback then your DAO might still commit.
I would try to make the session bean use CMT, that is the most flexible if you are staying within the appserver.
Hope that helps,
Guy
http://www.atomikos.com

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HOWTO: Using a BC4J Application Module in an Stateless EJB Session Bean

HOWTO: Using a BC4J Application Module in an Stateless EJB Session Bean
by Steve Muench
Overview
BC4J provides automatic facilities for deploying any application module as a stateful EJB session bean. If you want to leverage the features of your BC4J application module from a stateless EJB session bean, it's not automatic but it is straightforward to implement. This howto article explains the details.
For our example, we will create a stateless EJB session bean that uses a container-managed transaction. To keep things simple, let's assume the session bean has a single public method on its remote interface named createDepartment() with the following signature:
public void createDepartment(int id, String name, String loc) throws AppException
AppException is an example of an application-specific exception that our method will throw if any problems arise during its execution.The goal of this article is to illustrate how to use the BC4J application module named com.example.hr.HRApp as part of the implementation of this createDepartment method on our stateless enterprise bean. Let's assume that the HRApp application module has a view object member named Departments, based on the com.example.hr.DeptView view object, based on the familiar DEPT table and related to the com.example.hr.Dept entity object so our view can be updateable.
Creating the Stateless Session Bean
We can start by using the JDeveloper Enterprise Bean wizard to create a new stateless session bean called StatelessSampleEJB implemented by:[list][*]com.example.StatelessSampleEJBBean (Bean class)[*]com.example.StatelessSampleEJBHome (Home interface)[*]com.example.StatelessSampleEJB (Remote interface)[list]
We then use the EJB Class Editor to add the createDepartment method to the remote interface of StatelessSampleEJB with the signature above. We edit the remote interface to make sure that it also reflects that the createDepartment method thows the AppException like this:
package com.example;
import javax.ejb.EJBObject;
import java.rmi.RemoteException;
public interface StatelessSampleEJB extends EJBObject {
void createDepartment(int id, String name, String loc)
throws RemoteException,AppException;
}Before we start adding BC4J into the picture for our implementation, our StatelessSampleEJBBean class looks like this:
package com.example;
import javax.ejb.SessionBean;
import javax.ejb.SessionContext;
public class StatelessSampleEJBBean implements SessionBean {
public void ejbCreate(){}
public void ejbActivate(){}
public void ejbPassivate(){}
public void ejbRemove(){}
public void setSessionContext(SessionContext ctx){
public void createDepartment(int id, String name, String loc)
throws AppException {
    // TODO: Implement method here
}We can double-click on the ejb-jar.xml file in our project to see the XML deployment descriptor for the bean we just created:
<ejb-jar>
   <enterprise-beans>
      <session>
         <description>Session Bean ( Stateless )</description>
         <display-name>StatelessSampleEJB</display-name>
         <ejb-name>StatelessSampleEJB</ejb-name>
         <home>com.example.StatelessSampleEJBHome</home>
         <remote>com.example.StatelessSampleEJB</remote>
         <ejb-class>com.example.StatelessSampleEJBBean</ejb-class>
         <session-type>Stateless</session-type>
         <transaction-type>Container</transaction-type>
      </session>
   </enterprise-beans>
</ejb-jar>We need to add the extra <assembly-descriptor> section in this file to indicate that the createDepartment method will require a transaction. After this edit, the ejb-jar.xml file looks like this:
<ejb-jar>
   <enterprise-beans>
      <session>
         <description>Session Bean ( Stateless )</description>
         <display-name>StatelessSampleEJB</display-name>
         <ejb-name>StatelessSampleEJB</ejb-name>
         <home>com.example.StatelessSampleEJBHome</home>
         <remote>com.example.StatelessSampleEJB</remote>
         <ejb-class>com.example.StatelessSampleEJBBean</ejb-class>
         <session-type>Stateless</session-type>
         <transaction-type>Container</transaction-type>
      </session>
   </enterprise-beans>
   <assembly-descriptor>
      <container-transaction>
         <method>
            <ejb-name>StatelessSampleEJB</ejb-name>
            <method-name>createDepartment</method-name>
            <method-params>
               <method-param>int</method-param>
               <method-param>java.lang.String</method-param>
               <method-param>java.lang.String</method-param>
            </method-params>
         </method>
         <trans-attribute>Required</trans-attribute>
      </container-transaction>
   </assembly-descriptor>
</ejb-jar>
Aggregating a BC4J Application Module
With the EJB aspects of our bean setup, we can proceed to implementing the BC4J application module aggregation.
The first thing we do is add private variables to hold the EJB SessionContext and the instance of the aggregated BC4J ApplicationModule, like this:
// Place to hold onto the aggregated appmodule instance
transient private ApplicationModule _am = null;
// Remember the SessionContext that the EJB container provides us
private           SessionContext    _ctx = null;and we modify the default, empty implementation of the setSessionContext() method to remember the session context like this:
public void setSessionContext(SessionContext ctx){ _ctx = ctx; }We add additional constants that hold the names of the J2EE datasource that we want BC4J to use, as well as the fully-qualified name of the BC4J application module that we'll be aggregating:
// JNDI resource name for the J2EE datasource to use
private static final String DATASOURCE = "jdbc/OracleCoreDS";
// Fully-qualified BC4J application module name to aggregate
private static final String APPMODNAME = "com.example.hr.HRApp";We expand the now-empty ejbCreate() and ejbRemove() methods to create and destory the aggregated instance of the BC4J application module that we'll use for the lifetime of the stateless session bean. When we're done, ejbCreate() it looks like this:
public void ejbCreate() throws CreateException {
try {
    // Setup a hashtable of environment parameters for JNDI initial context
    Hashtable env = new Hashtable();
    env.put(JboContext.INITIAL_CONTEXT_FACTORY,JboContext.JBO_CONTEXT_FACTORY);
    // NOTE: we want to use the BC4J app module in local mode as a simple Java class!
    env.put(JboContext.DEPLOY_PLATFORM, JboContext.PLATFORM_LOCAL);
    env.put(PropertyConstants.INTERNAL_CONNECTION_PARAMS,DATASOURCE);
    // Create an initial context, using this hashtable of environment params
    InitialContext ic = new InitialContext(env);
    // Lookup a home interface for the application module
    ApplicationModuleHome home = (ApplicationModuleHome)ic.lookup(APPMODNAME);
    // Using the home, create the instance of the appmodule we'll use
    _am = home.create();
    // Register the BC4J factory to handle EJB container-managed transactions
    registerContainerManagedTransactionHandlerFactory();
catch(Exception ex) {
     ex.printStackTrace();
    throw new CreateException(ex.getMessage());
}and ejbRemove() looks like this:
public void ejbRemove() {
try {
    // Cleanup any appmodule resources before getting shutdown
    _am.remove();
catch(JboException ex) { /* Ignore */ }
}The helper method named reigsterContainerManagedTransactionHandlerFactory() looks like this:
private void registerContainerManagedTransactionHandlerFactory() {
SessionImpl session = (SessionImpl)_am.getSession();
session.setTransactionHandlerFactory(
    new TransactionHandlerFactory() {
      public TransactionHandler createTransactionHandler() {
        return new ContainerManagedTxnHandlerImpl();
      public JTATransactionHandler createJTATransactionHandler() {
        return new ContainerManagedTxnHandlerImpl();
}The last detail is to use the BC4J appmodule to implement the createDepartment() method. It ends up looking like this:
public void createDepartment(int id, String name, String loc)
throws AppException {
try {
    // Connect the AM to the datasource we want to use for the duration
    // of this single method call.
    _am.getTransaction().connectToDataSource(null,DATASOURCE,false);
    // Use the "Departments" view object member of this AM
    ViewObject departments = _am.findViewObject("Departments");
    // Create a new row in this view object.
    Row newDept = departments.createRow();
    // Populate the attributes from the parameter arguments.
    newDept.setAttribute("Deptno", new Number(id));
    newDept.setAttribute("Dname", name);
    newDept.setAttribute("Loc", loc);
    // Add the new row to the view object's default rowset
    departments.insertRow(newDept);
    // Post all changes in the AM, but we don't commit them. The EJB
    // container managed transaction handles the commit.
    _am.getTransaction().postChanges();
catch(JboException ex) {
    // To be good EJB Container-Managed Transaction "citizens" we have
    // to mark the transaction as needing a rollback if there are problems
    _ctx.setRollbackOnly();
    throw new AppException("Error creating dept "+ id +"\n"+ex.getMessage());
finally {
    try {
      // Disconnect the AM from the datasource we're using
      _am.getTransaction().disconnect();
    catch(Exception ex) { /* Ignore */ }
Building a Test Client
With the EJB-Tier work done, we can build a sample client program to test this new stateless EJB Session Bean by selecting the bean in the Oracle9i JDeveloper IDE and choosing "Create Sample Java Client" from the right-mouse menu.
When the "Sample EJB Client Details" dialog appears, we take the defaults of connecting to embedded OC4J container. Clicking the (OK) button generates the following test class:
import java.util.Hashtable;
import javax.naming.Context;
import javax.naming.InitialContext;
import com.example.StatelessSampleEJB;
import com.example.StatelessSampleEJBHome;
public class SampleStatelessSampleEJBClient {
public static void main(String [] args) {
    SampleStatelessSampleEJBClient sampleStatelessSampleEJBClient =
       new SampleStatelessSampleEJBClient();
    try {
      Hashtable env = new Hashtable();
      env.put(Context.INITIAL_CONTEXT_FACTORY,
              "com.evermind.server.rmi.RMIInitialContextFactory");
      env.put(Context.SECURITY_PRINCIPAL, "admin");
      env.put(Context.SECURITY_CREDENTIALS, "welcome");
      env.put(Context.PROVIDER_URL,
              "ormi://localhost:23891/current-workspace-app");
      Context ctx = new InitialContext(env);
      StatelessSampleEJBHome statelessSampleEJBHome =
           (StatelessSampleEJBHome)ctx.lookup("StatelessSampleEJB");
      StatelessSampleEJB statelessSampleEJB;
      // Use one of the create() methods below to create a new instance
      // statelessSampleEJB = statelessSampleEJBHome.create();
      // Call any of the Remote methods below to access the EJB
      // statelessSampleEJB.createDepartment( int id, java.lang.String name, java.lang.String loc );
    catch(Throwable ex) {
      ex.printStackTrace();
}We uncomment the call to the create() method and add a few calls to the createDepartment() method so that the body of the test program now looks like this:
// Use one of the create() methods below to create a new instance
statelessSampleEJB = statelessSampleEJBHome.create();
// Call any of the Remote methods below to access the EJB
statelessSampleEJB.createDepartment( 13, "Test1","Loc1");
System.out.println("Created department 13");
statelessSampleEJB.createDepartment( 14, "Test2","Loc2");
System.out.println("Created department 14");
try {
// Try setting a department id that is too large!
statelessSampleEJB.createDepartment( 23456, "Test3","Loc3");
catch (AppException ax) {
System.err.println("AppException: "+ax.getMessage());
}Before we can successfully run our SampleStatelessSampleEJBClient we need to first run the EJB bean that the client will try to connect to. Since Oracle9i JDeveloper supports local running and debugging of the EJB-Tier without doing through a full J2EE deployment step, to accomplish this prerequisite step we just need to right-mouse on the StatelessSampleEJB node in the System Navigator and select "Run". This starts up the embedded OC4J instance and runs the EJB right out of the current out path.Finally, we can run the SampleStatelessSampleEJBClient, and see the output of the test program in the JDeveloper log window:
Created department 13
Created department 14
AppException: Error creating dept 23456
JBO-27010: Attribute set with value 23456 for Deptno in Dept has invalid precision/scale
Troubleshooting
One error that might arise while running the example is that the database connection information in your data-sources.xml for the jdbc/OracleCoreDS datasource does not correspond to the database you are trying to test against. If this happens, then double-check the file .\jdev\system\oc4j-config\data-sources.xml under the JDeveloper installation home directory to make sure that the url value provided is what you expect. For example, to work against a local Oracle database running on your current machine, listening on port 1521, with SID of ORCL, you would edit this file to have an entry like this for jdbc/OracleCoreDS :
<data-source
    class="com.evermind.sql.DriverManagerDataSource"
    name="OracleDS"
    location="jdbc/OracleCoreDS"
    xa-location="jdbc/xa/OracleXADS"
    ejb-location="jdbc/OracleDS"
    connection-driver="oracle.jdbc.driver.OracleDriver"
    username="scott"
    password="tiger"
    url="jdbc:oracle:thin:@localhost:1521:ORCL"
    inactivity-timeout="30"
/>This is the data-sources.xml file that gets used by the embedded OC4J instance running in JDeveloper.
Conclusion
Hopefully this article has illustrated that it is straightforward to utilize the full power of BC4J in local mode as part of your EJB Stateless Session Beans using container-managed transaction. This example illustrated a single createDepartment method in the enterprise bean, but by replicating the application module interaction code that we've illustrated in createDepartment, any number of methods in your stateless session bean can use the aggregated application module instance created in the ejbCreate() method.
Code Listing
The full code listing for the SampleStatelessEJB bean implementation class looks like this:
* StatelessSampleEJB
* Illustrates how to use an aggregated BC4J application module
* in local mode as part of the implementation of a stateless
* EJB session bean using container-managed transaction.
* HISTORY
* smuench/dmutreja 14-FEB-2002 Created
package com.example;
import oracle.jbo.*;
import oracle.jbo.server.*;
import javax.ejb.*;
import oracle.jbo.domain.Number;
import oracle.jbo.common.PropertyConstants;
import java.util.Hashtable;
import javax.naming.InitialContext;
import oracle.jbo.server.ejb.ContainerManagedTxnHandlerImpl;
public class StatelessSampleEJBBean implements SessionBean {
// JNDI resource name for the J2EE datasource to use
private static final String DATASOURCE = "jdbc/OracleCoreDS";
// Fully-qualified BC4J application module name to aggregate
private static final String APPMODNAME = "com.example.hr.HRApp";
// Place to hold onto the aggregated appmodule instance
transient private ApplicationModule _am = null;
// Remember the SessionContext that the EJB container provides us
private           SessionContext    _ctx = null;
public void ejbCreate() throws CreateException {
    try {
      // Setup a hashtable of environment parameters for JNDI initial context
      Hashtable env = new Hashtable();
      env.put(JboContext.INITIAL_CONTEXT_FACTORY,JboContext.JBO_CONTEXT_FACTORY);
      env.put(JboContext.DEPLOY_PLATFORM, JboContext.PLATFORM_LOCAL);
      env.put(PropertyConstants.INTERNAL_CONNECTION_PARAMS,DATASOURCE);
      // Create an initial context, using this hashtable of environment params
      InitialContext ic = new InitialContext(env);
      // Lookup a home interface for the application module
      ApplicationModuleHome home = (ApplicationModuleHome)ic.lookup(APPMODNAME);
      // Using the home, create the instance of the appmodule we'll use
      _am = home.create();
      // Register the BC4J factory to handle EJB container-managed transactions
      registerContainerManagedTransactionHandlerFactory();
    catch(Exception ex) {
       ex.printStackTrace();
      throw new CreateException(ex.getMessage());
public void ejbActivate(){}
public void ejbPassivate(){}
public void ejbRemove(){}
public void setSessionContext(SessionContext ctx){ _ctx = ctx; }
public void createDepartment(int id, String name, String loc)
throws AppException {
    try {
      // Connect the AM to the datasource we want to use for the duration
      // of this single method call.
      _am.getTransaction().connectToDataSource(null,DATASOURCE,false);
      // Use the "Departments" view object member of this AM
      ViewObject departments = _am.findViewObject("Departments");
      // Create a new row in this view object.
      Row newDept = departments.createRow();
      // Populate the attributes from the parameter arguments.
      newDept.setAttribute("Deptno", new Number(id));
      newDept.setAttribute("Dname", name);
      newDept.setAttribute("Loc", loc);
      // Add the new row to the view object's default rowset
      departments.insertRow(newDept);
      // Post all changes in the AM, but we don't commit them. The EJB
      // container managed transaction handles the commit.
      _am.getTransaction().postChanges();
    catch(JboException ex) {
      // To be good EJB Container-Managed Transaction "citizens" we have
      // to mark the transaction as needing a rollback if there are problems
      _ctx.setRollbackOnly();
      throw new AppException("Error creating dept "+ id +\n"+ex.getMessage());
    finally {
      try {
        // Disconnect the AM from the datasource we're using
        _am.getTransaction().disconnect();
      catch(Exception ex) { /* Ignore */ }
private void registerContainerManagedTransactionHandlerFactory() {
    SessionImpl session = (SessionImpl)_am.getSession();
    session.setTransactionHandlerFactory(
      new TransactionHandlerFactory() {
        public TransactionHandler createTransactionHandler() {
          return new ContainerManagedTxnHandlerImpl();
        public JTATransactionHandler createJTATransactionHandler() {
          return new ContainerManagedTxnHandlerImpl();

Hi Steve, It4s me again;
About the question I made, I tried with a single assembly-descriptor tag and a single container-transaction tag in the deployment descriptor of the session bean and these were the results.
java.lang.NullPointerException
     void com.evermind.server.rmi.RMIConnection.EXCEPTION_ORIGINATES_FROM_THE_REMOTE_SERVER(java.lang.Throwable)
     java.lang.Object com.evermind.server.rmi.RMIConnection.invokeMethod(com.evermind.server.rmi.RMIContext, long, long, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.rmi.RemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.rmi.RecoverableRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.ejb.StatelessSessionRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     void __Proxy1.modificaEnvoltura(java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.String)
     void SamplemdeController.envolturaControlEJBClient.main(java.lang.String[])
Then I tried with multiple assembly-descriptor tags each with a single container-transaction tag and the results were:
java.lang.NullPointerException
     void com.evermind.server.rmi.RMIConnection.EXCEPTION_ORIGINATES_FROM_THE_REMOTE_SERVER(java.lang.Throwable)
     java.lang.Object com.evermind.server.rmi.RMIConnection.invokeMethod(com.evermind.server.rmi.RMIContext, long, long, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.rmi.RemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.rmi.RecoverableRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.ejb.StatelessSessionRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     void __Proxy1.modificaEnvoltura(java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.String)
     void SamplemdeController.envolturaControlEJBClient.main(java.lang.String[])
Finally I tried with a single assembly-descriptor and multiple container tags and the results were:
java.lang.NullPointerException
     void com.evermind.server.rmi.RMIConnection.EXCEPTION_ORIGINATES_FROM_THE_REMOTE_SERVER(java.lang.Throwable)
     java.lang.Object com.evermind.server.rmi.RMIConnection.invokeMethod(com.evermind.server.rmi.RMIContext, long, long, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.rmi.RemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.rmi.RecoverableRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     java.lang.Object com.evermind.server.ejb.StatelessSessionRemoteInvocationHandler.invoke(java.lang.Object, java.lang.reflect.Method, java.lang.Object[])
     void __Proxy1.modificaEnvoltura(java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.String)
     void SamplemdeController.envolturaControlEJBClient.main(java.lang.String[])
How can I make my Stateless Session bean work out?

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

Problem using application client for local stateful session bean

Hi,
I have deployed a local stateful session bean in Sun J2EE 1.4 application server.
On running the applclient for the stateful session bean application client i get the following error:
Warning: ACC006: No application client descriptor defined for: [null]
cant we use application client for local stateful session beans. becoz the application runs smoothly when i changed the stateful sesion bean to remote.

Hi,
No, an ejb that exposes a local view can only be accessed by an ejb or web component packaged within the same application. Parameters and return values for invocations through the ejb local view are passed by reference instead of by value. That can't work for an application client since it's running in a separate JVM.
--ken

How to make a session bean interact with a entity bean?

hi,
An entity bean has been created and tested successfully. Values entered into the test app are successfully entered into the pointbase db.
Now trying to create the same feature through session beans. when the method is invoked, it appears ok, but when the database is queried the values have not been entered. Is there anything that could have been missed or incorrect?
the steps to setting up session bean
1)add code to create for JNDI lookup
public void ejbCreate() {
System.out.println("Entering oneManagerEJB.ejbCreate()");
Context c = null;
Object result = null;
if (this.myoneHome == null) {
try {
c = new InitialContext();
result =
c.lookup("java:comp/env/ejb/one");
myoneHome =
(oneHome)javax.rmi.PortableRemoteObject.narrow(result,
oneHome.class);
catch (Exception e) {System.out.println("Error: "+
e); }
2) add business method to enter values into entity bean
public void createone(int number) {
System.out.println("Entering ");
try {
one oneinfo =
myoneHome.create(number);
} catch (Exception e) {
// Join the following two lines in the Source Editor
System.out.println("Error in " + e);
// Join the following two lines in the Source Editor
System.out.println("Leaving ");
3) declare variables and namings
import javax.naming.*;
private oneHome myoneHome;
4) add reference to logical session bean
ejb/one
5) create test app and add entity bean "one" to module. check mappings.
run app

I would do several things which will help track down the problem:
1. Where you have println statements you may want to change these to exceptions, the session bean won't really work if these problems occur and may silently fail. For example, throw a runtime exeption or EJBException to indicate that the entity bean home interface cannot be found.
2. When you create the test application you should replace the ejb module which is automatically created with the ejb module or module(s) containing both of the ejb's. This will ensure that the configuration is preserved. The test application is a standard J2EE application, so modules can be added (you could even have multiple test applications each testing a different ejb, make sure that you use different context roots).
Chris

A simple class vs. Stateless Session Bean

If I want a stateless bean to do some simple work such as give it a number A
          and get A+10 in return, does the Stateless session bean really perform
          better than a simple class? In my project, there are lots of simple job like
          this, which one should I use? A Stateless session bean or a simple class?
          Besides, when is the right time to use a stateful session bean? I use the
          servlet to keep user information in the session, and than have the stateless
          session bean working with it...This pattern meets most requirement....So I'm
          wondering in what situation should I need to use stateful session bean?
          Thanks!


- It is far better to use a stateless session bean when implementing the session-facade pattern.
- Keeping a home interface on the object won't make him stateful.
- with the stateless beans, you do not decide when they're created. The container does.
- The number of entity beans is not so important. The only thing important is to have a remote methode in your stateless(es) for each atomic transaction ("atomic" meaning here "you cannot cut").
/Stephane

Urgent - (session bean calling Entity bean )Help Need for me - Plzzzzzzzzzz

Hi
I am created two beans one is Entity bean another one is session . the two beans deployed using diffrent jar files
. I call the Entity bean methods using session bean
But i couldn't locate the entity bean Home object through session bean(
Sub is created but i couldn't get it that home obj stub)
i get the following error messgae CorbaBad Operation
i deployed two bean using same jar means my program is working
Help meeeeeee

I Send part of code to u
public String logic1(rsp.ejbbm.ex.studVO s) {
          rsp.ejbbm.student.studentRemote r=null;
          String id = null;
          try {
System.out.println("sdfsdfsdfs");
          Object obj = ctx.lookup("ejb/student");
          System.out.println("Lookup Succeded ");
          System.out.println("Object value" +obj.toString());
/// HERE I GOT THE ERRO I COULDn'T Locate IT
EJBHome obj1 =(EJBHome)javax.rmi.PortableRemoteObject.narrow(obj,rsp.ejbbm.student.studentHome.class);
          System.out.println("Object value" +obj1.toString());
          rsp.ejbbm.student.studentHome home=(rsp.ejbbm.student.studentHome)obj1;
          //studentHome hom=(studentHome)ctx.lookup("ejb/student");
     System.out.println("Object value" +obj.toString() );
     System.out.println("Lookup Converted ");
          home.create(s.getRollno(),s.getName());
          System.out.println("student Record isInserted in Oracle ");
          r= (rsp.ejbbm.student.studentRemote) home.findByPrimaryKey(s.getRollno());
          System.out.println("Student 5555 Name is "+ r.getName());
          id = r.getName();
          catch(Exception e ){
          System.out.println(e.toString());}
          return id;
* @see javax.ejb.SessionSynchronization#afterBegin()
public void afterBegin() {
* @see javax.ejb.SessionSynchronization#afterCompletion(boolean)
public void afterCompletion(boolean committed) {
* @see javax.ejb.SessionSynchronization#beforeCompletion()
public void beforeCompletion() {
* See section 7.10.3 of the EJB 2.0 specification
public void ejbCreate() {
          Properties p = new Properties();
          p.put("java.naming.factory.initial", "com.sun.jndi.cosnaming.CNCtxFactory");
          try{
     ctx = new InitialContext(p);
     catch(Exception e) {System.out.println("Create Exception "+e.toString());}
}

Hot delpoyment with TopLink and Stateless Session Beans

What is the recommended procedure for making hot deployment of Stateless session beans work with toplink in WLS 7.0sp1 and oc4j (9.0.3)
My current setup is as follows using WLS 7.0sp1:
A stateless session bean is accessing toplink enabled persistent java classes via the SessionManager. I'm currently using the class loader of the stateless session bean:
* Method in stateless session bean
* Return the TopLink Session (based on the wls stateless session bean demo)
public Server getSession() {
return (Server)SessionManager.getManager().getSession("ejb_sessionbean", this.getClass().getClassLoader());
Everything is working as such. My session bean can read and write the persistent java classes. However if I redeploy the stateless session bean jar file the toplink session is not reinitalized. This means that new settings in the session.xml are not used. I addition I get other errors.
I'm having toplink on the server classpath. The toplink enabled persistent classes are in the stateless session bean jar file.
Thanks
Henrik

What is the recommended procedure for making hot deployment of Stateless session beans work with toplink in WLS 7.0sp1 and oc4j (9.0.3)
Everything is working as such. My session bean can read and write the persistent java classes. However if I redeploy the stateless session bean jar file the toplink session is not reinitalized. This means that new settings in the session.xml are not used. I addition I get other errors.
I'm having toplink on the server classpath. The toplink enabled persistent classes are in the stateless session bean jar file.Henrik,
This is a recent post note I found on the same topic:
It all hinges on whether the TopLink ServerSession class has
been loaded by a classloader which is actually thrown away
during the hot deployment process. If this is the case, then
hot deployment causes the ServerSession to go out of scope
and finalize methods take care of logging it out properly.
If you deploy your TopLink Project on the Sytem class path then
it definately won't work. You'd have to restart the server every time.
But if the TopLink Project is deployed inside of an .ear file
and if you pass the correct ClassLoader to the
SessionManager.getSession( .... ) call then TopLink Session will
be re-started when you hot deploy the .earBased on this, the solution might be to deploy your EJBs in an ear file. Everything else looks OK. Can you try this and let us know?
Thanks,
Pete Farkas

Transaction management in BMP through Session bean(worked in J2EE RI)

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