How does a session bean find entity beans in EJB 3.0

Hi,
I am new to J2EE. I have difficulties finding out how a session bean locates the entity-manager for a group of entity beans. I understand that the entitymanager in the session bean is injected using the PersistenceContext annotation, but I dont see how it locates the intended EntityManager (which could be on another server).
I realize this is probably trivial, but can any of you guys tell me what I am missing?
Best Regards
Thomas

Hi Thomas,
Good question. Each @PersistenceContext annotation is associated with a single Persistence Unit. A Persistence Unit is defined either at the module level or at the .ear level. Each persistence unit has a name associated with it. The unitName() attribute is used to map @PersistenceContext to the associated PersistenceUnit. Since the most common case is that an application will only define one persistence unit, the spec requires that if the unitName() is not specified, it will automatically map to that single persistence unit.
--ken

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Need of session bean in ejb?

We can have the session beans business logic in Servlet using some support class(may be bean).I would like to know exact purpose & use of session bean in ejb specification.

We can have the session beans business logic in
Servlet using some support class(may be bean).I would
like to know exact purpose & use of session bean in
ejb specification.You can think of a SessionBean as a script. It handles certain business logic, for example, like book a flight. It might get the itinerary, charge the credit card, book a flight, etc. Usually, it is used as a facade, or front to one or more entity beans.
Now, you could do these exact same things with servlets, but the session bean allows you to have:
1. A single transaction scope. If one of your processes throws an exception and you've updated, for example 2 database tables, this transaction can be rolled back and everything will be consistant.
2. Servlets, by nature, are threaded and you have to take special care with synchronization issues of any member variables that you may use in the servlet. With EJBs there are no synchronization issues.
3. Security. You can specifically disallow/allow access to methods based on roles that you define.
These are the big reasons for using EJBs. Yes, you can do all of this with servlets, but you'd have to do it yourself ... but why do it, if it is already done for you.
I hope that that clears things up.
Regards,
Paul

How to call session bean's method in JSP

Hi All,
I am working on a JSF web application by using sun studio creator.
The first page have a button, the onClick javascript is as following, which bring up a alert box showing user login name.
In JSP file, how can I call session bean's setUserName(String name) function (which I would like to store this UserName). So the following pages can use this information.
If I can not do it this way, is there any other way to do it?
Thanks in advance.
var net = new ActiveXObject("wscript.network");
alert(net.UserName);
In managed-beans.xml
<managed-bean>
<managed-bean-name>BasicInfo</managed-bean-name>
<managed-bean-class>treepractice.BasicInfo</managed-bean-class>
<managed-bean-scope>session</managed-bean-scope>
</managed-bean>

You can find more information/details/examples at their own website.
On the other hand, do you realize that that ActiveX stuff is IE proprietary? And that it is a browser configuration whether to allow them or not? And that this configuration is in IE7 defaulted to an (annoying) warning box before execution which is just bad for the user experience?
With other words, forget that ActiveX garbage. Alternatives are Applets (not recommended) or Java Web Start (recommended).

How to delete session bean data

Hi,
My requirement is to default the data while selected in LOV. so i have written written custom code for that using valueChangeListener.
public void getCustomerDetails(ValueChangeEvent valueChangeEvent) {
// Add event code here...
try{
String cardNumber= valueChangeEvent.getNewValue().toString();
System.out.println("card no is: "+cardNumber);
String cardNo="000601029500"+cardNumber;
session.setCardNo(cardNo);
HashMap map=getAm().getCustomerDetails1(cardNumber);
Set set=map.entrySet();
Iterator i = set.iterator();
while(i.hasNext()){
i.next();
if(map.get("customer_name")!=null){
customer_name=map.get("customer_name").toString();
session.setCustName(customer_name);
//System.out.println("customer_name: "+customer_name);
else{
customer_name=null;
In the page:
<af:inputText value="#{SCIISessionBean.merchantName}"
label="#{avtransuiBundle.MERCHANT_NAME}"
required="#{bindings.MerchantName.hints.mandatory}"
columns="#{bindings.MerchantName.hints.displayWidth}"
maximumLength="#{bindings.MerchantName.hints.precision}"
shortDesc="#{bindings.MerchantName.hints.tooltip}"
partialTriggers="ilov1"
binding="#{backingBeanScope.backing_com_wfs_avtranz_newAvtranzSubmit.it1}"
id="it1" readOnly="true">
<f:validator binding="#{bindings.MerchantName.validator}"/>
</af:inputText>
But here my issues is because of putting the value in Session bean it is not clearing when i come to next page to this page. the values are remaining same. i try with request scope and page flow scope because of these when i select any button on or any popup on the page, it got refresh and value is disappering on the page. that's why i have taken session but still session values i am able to see.
can any one tell me how can i make this values as null;

User, you must understand that many of us DO read posts, and do answer questions if we can. But this is NOT our primary job - we do it as a service to our fellow users WHEN WE HAVE TIME. Also, none of us knows everything there is to know - it may be a few days before one of the people who can answer YOUR question will see it and answer. Finally, there are some questions for which no-one will know the answer. Keep working, and maybe you will learn something that YOU can tell US.
Okay, now that that is off my chest:
Values in a session bean start with whatever you initialize them to - either when the property is defined, or in the constructor for the bean. A valueChangeListener can't change the value - this is executed when the USER changes the value. It could be used to drive a change to a different value, but make sure that you set the component with a valueChangeListener to autosubmit, and use partial page rendering to re-render the changed component.
If you need to clear data from a session bean, you will need to write a method to do it. You could write it as an actionListener, and have the user press a Clear button, or as a helper method that gets called as part of some other action. I think that you can also arrange to call it before a page renders, but I haven't had occasion to do that, so I've never researched how to do it.
P.S. When I re-read your post, and tried to understand better what you really want to do, I suddenly realized that you have a classic use-case of a cascading list of values. In other words, the contents of one list of values changes depending on what is selected in another list. If you will look through the tutorials on the main ADF page, I think you will find at least one example of how to do this.

How to intantiate Stateful session bean in EJB 3 ?

In EJB 2.x, to instantiate a Stateful Session bean the process was:
1. Lookup Home object
2. call create(args) method on Home, that in turn would call corresponding ejbCreate(args) on the bean implementation.
Now, in EJB 3, there is no concept of Home interaface, How can I instantiate a stateful session bean with some initialization parameters.
Thanks

Just the spec. NetBeans should only be providing the ability to add an ejbCreate method if the bean exposes a Local or Remote 2.x view.
Each lookup or injection of a stateful session bean results in a new bean instance. As long as you call your methods to populate the additional
state right after first acquiring the stateful session bean reference it will work.
--ken

How to get session bean values in voimpl classes

Hi Experts,
To access session values in voimpl the below lines works fine.
Map sessionScope = ADFContext.getCurrent().getSessionScope();
String userName = (String)sessionScope.get("userName");
Can any one please help me in getting the values from session bean in voimpl.
Regards
Gayaz

Hi Jabr,
Please have a look into this post. This is for implementing ADF search and pass bind variables while performing search.
how to pass bind parameters while performing search
Regards
Gayaz

The client is a pure-Java client, how to invoke session bean in oc4j server

I WOULD LIKE TO INVOKE MY SESSION BEAN FROM MY STRUT WEB PROJECT AS A PURE JAVA CLIENT . I SETUP THE JNDI INITIAL CONTEXT PROPERTY BUT I HAVE NO IDEA TO WHERE I SHALL PUT MY application-client.xml and orion-application-client.xml. MY APPLICATION THROW EXCEPTION
NamingException: StoreEJB not found
IF YOU ANY EXAMPLE PLEASE SEND ME
THIS IS MY CLIENT PROGRAME
package ejbs;
import java.io.*;
import javax.ejb.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.naming.*;
import javax.rmi.*;
import java.rmi.*;
import java.util.*;
public class StrutInt {
     * @param args
     public static void main(String[] args) {
          //System.out.print("The application Checkup");
          try
               Hashtable env = new Hashtable();
               env.put (Context.INITIAL_CONTEXT_FACTORY,
               "oracle.j2ee.naming.ApplicationClientInitialContextFactory");
               env.put (Context.SECURITY_PRINCIPAL, "oc4jadmin");
               env.put (Context.SECURITY_CREDENTIALS, "admin");
               //env.put (Context.PROVIDER_URL, "http://localhost:8888");
               env.put (Context.PROVIDER_URL, "ormi://localhost:23791/EjbIntegrationEAR");
               env.put ("dedicated.rmicontext", "true"); // for 9.0.2.1 and above
               Context context = new InitialContext (env);
               System.out.println("work up to this");
          Object homeObject =
context.lookup("StoreEJB");
          System.out.print("Hi Integration");
     StoreHome storeHome = (StoreHome) PortableRemoteObject
               .narrow(homeObject, StoreHome.class);
     Store exa= storeHome.create();
          String s =exa.foo("The foul guy");
          System.out.print(s);
     catch(NamingException e1) {
     System.err.println("NamingException: " + e1.getMessage());
     catch(RemoteException e2) {
     System.err.println("RemoteException: " + e2.getMessage());
     catch(CreateException e3) {
     System.err.println("FinderException: " + e3.getMessage());
     catch(Exception e4) {
     System.err.println("FinderException: " + e4.getMessage());
     }

Create the object of InitialContest class. Then pass in hashTable put WLContextFactory.
then lookup to the sessionJNDI. then call the create method u will get the remote object, from the remote object u can call to the business method

Calling Enity Bean's business methods from a session bean in EJB 3.0 specif

Hello everybody,
Happy to be a member with you in this forum.
This is my first participation in this forum.
I have some problem to start with EJB 3.0 specification, I have created an entity bean with some business methods that access a mysql datbase, then i want to create a stateful session bean to provide the client an interface to consume business methods in Enity be
Please can someone you help me with an example

@Vladimir Pavlov
I did not understand what you are trying to convey...
Whenever an attribute of this bean is modified we want to access that latest value.... Is there any way to know, when the attribute is modified? Just with get/set we can not know, when it is modified... am i right?
We want to achieve this without modifying the existing source code of the EJB....
@ Ivo Simeonov
As of my knowledge, to use interceptors we need to modify the EJB source code, but we do not want to touch the source code....
All this has to be achieved dynamically when the application is deployed in the production.... is it possible???

Stateful Session Bean Initialization (EJB 3.0)

Hi all!
In EJB 2.1 the initialization was with create (args) methods. NOw, how is it exploited? Create methods are no more there and there must be a way to send parameters to the stateful session bean when it is newly created...isn't it?
Thank you!

There is no pre-defined equivalent of a create method in EJB 3.0. If you want to initialize a
stateful session bean, just define a business method that the client should use as an initialization
method.

Local session bean lookup in another local session bean in EJB 3.0

Hi,
I am doing JNDI lookup of a local session bean in a session bean. ( I do not want to use EJB dependency injection).
Lookup of local interface from session bean is successful. But, when the calling session bean is a local session in another session bean, the lookup fails.
Here is an example:
@Stateless
@EJBs({@EJB(name="EJB2Local", beanInterface=EJB2Local.class),
@EJB(name="EJB3Local", beanInterface=EJB3Local.class)})
public class EJB1 implements EJB1Remote, EJB1Local{
public void findEJB3Local(){
//1. JNDI lookup for EJB3Local ----
//2. EJB3Local.someFunction()
@Stateless
@EJB(name="EJB1Local", beanInterface=EJB1Local.class)
public class EJB2 implements EJB2Remote, EJB2Local{
public void findEJB1Local(){
//1. JNDI lookup EJB1Local
// 2. Call EJB1Local.findEJB1Local method
//THIS METHOD CALL WILL FAIL.
public void findEJB1Remote(){
//1. JNDI lookup EJB1
/ 2. Call EJB1Local.findEJB1 method
@Stateless
public class EJB3 implements EJB3Remote, EJB3Local{
public void someFunction(){}
This setup was working in EJB 2.1, as we had clear ejb-local-ref definitions in our ejb-jar.xml file.
I am suspecting that EJB 3.0 has special annotation to use when lookup is made from another local session bean.
Any comments will be appreciated.
Thanks,
Mohan

From a private component environment perspective, declaring @EJB in a bean class is equivalent
to using ejb-ref or ejb-local-ref for that same bean in ejb-jar.xml. In each case, the EJB dependency
is declared for that bean. Each EJB component has its own private component environment, so
code running within invocations on different EJBs can not see the component environment of the
components that made the invocations.
What exact error are you getting? Please post the stack trace if possible.
--ken

Local Session Bean calling another local Session Bean in EJB 3.0

Hi,
In EJB 3.0, I am trying to do JNDI lookup of a local sesion bean from another session bean's helper class.
I am not using @EJB injection mechanism here, as call to the local session bean is made in a helper class. Helper classes do not support resource injection.
Following are the EJB class definitions used in my project. Call to "EJB3Local" made from "EJB1" fails as the "EJB2" helper class is calling "EJB1Local"
@Stateless
@EJBs({@EJB(name="EJB2Local", beanInterface=EJB2Local.class),
@EJB(name="EJB3Local", beanInterface=EJB3Local.class)})
public class EJB1 implements EJB1Remote, EJB1Local{
public void findEJB3Local(){
//1. JNDI lookup for EJB3Local ----
//2. EJB3Local.someFunction()
@Stateless
@EJB(name="EJB1Local", beanInterface=EJB1Local.class)
public class EJB2 implements EJB2Remote, EJB2Local{
public void findEJB1Local(){
//1. JNDI lookup EJB1Local
// 2. Call EJB1Local.findEJB1Local method
@Stateless
public class EJB3 implements EJB3Remote, EJB3Local{
public void someFunction(){}
A remote call to EJB2.findEJB1Local() will invoke EJb1Local.findEJB3Local method and the call fails with "java:comp/env/EJB3Local" not found in EJB1Local.
Has anybody encountered an issue like this issue with local interface calling another local interface?
Thanks,
Mohan

To refer a Ejb from another Ejb include <ejb-ref> element
in ejb-jar.xml
<session>
<ejb-name>SessionBeanA</ejb-name>
<ejb-ref>
<ejb-ref-name>SessionBeanB</ejb-ref-name>
<ejb-ref-type>Session</ejb-ref-type>
<home>com.ejb.SessionBeanBHome</home>
<remote>com.ejb.SessionBeanB</remote>
</ejb-ref>
</session>
Include a <reference-descriptor> in weblogic-ejb-jar.xml
<weblogic-enterprise-bean>
<ejb-name>SessionBeanA</ejb-name>
<reference-descriptor>
<ejb-reference-description>
<ejb-ref-name>SessionBeanB</ejb-ref-name>
<jndi-name>com.ejb.SessionBeanBHome</jndi-name>
</ejb-reference-description>
</reference-descriptor>
</weblogic-enterprise-bean>
In SessionBeanA Bean class refer to SessionBeanB with
a remote reference to SessionBeanB.
InitialContext initialContext=new InitialContext();
SessionBeanBHome sessionBeanBHome=(SessionBeanBHome)
initialContext.lookup("com.ejb.SessionBeanBHome");
SessionBeanB sessionBeanB=sessionBeanBHome.findByPrimaryKey(primarykey);
sessionBeanB.update();
sessionBeanB.getAll();
thanks,
Deepak

EJB 2.1 session bean calling EJB 3 session bean?

I have a WL 10 (JDK 1.5/EE 5) server that has several EJB 3 stateless session beans deployed and working well. But now I need to allow a JBoss 3.2.3 (JDK 1.4) EJB 2.1 session bean make remote calls into these EJB 3 EJBs. Can this even work?
It seems to me that EJB 3 calling EJB 2 would be fine, but not in the reverse?

I have a WL 10 (JDK 1.5/EE 5) server that has several EJB 3 stateless session beans deployed and working well. But now I need to allow a JBoss 3.2.3 (JDK 1.4) EJB 2.1 session bean make remote calls into these EJB 3 EJBs. Can this even work?
It seems to me that EJB 3 calling EJB 2 would be fine, but not in the reverse?

How to deploy session bean.

I want to deploy Analyzer.jar on weblogic server,but there is an error information:
[J2EE:160043]Missing deployment descriptor "META-INF/ejb-jar.xml" at "D:\bea\user_projects\domains\test\applications\ejb\Analyzer.jar",in
fact there is ejb-jar.xml in Analyzer.jar.
please tell me the reason and how to configure ,thank you.
[Analyzer.jar]

Hi, I am having the same problem and was wondering if you were able to solve it
and how you did.
Thanks,
Luis
"Way" <[email protected]> wrote:
>
>
>
I want to deploy Analyzer.jar on weblogic server,but there is an error
information:
[J2EE:160043]Missing deployment descriptor "META-INF/ejb-jar.xml" at
"D:\bea\user_projects\domains\test\applications\ejb\Analyzer.jar",in
fact there is ejb-jar.xml in Analyzer.jar.
please tell me the reason and how to configure ,thank you.

How to use session bean connect to socket server?

Can any body provice an example for this?
Thank you.

Hi,
You have to catpture the "set-cookie" header from the response which you got in the first request. The same "set-cookie" value has to be set in the subsequent requests' header. Please see the below code snippet to collect the "set-cookie" and set the cookie in the subsequest requests.
//how to Collect the "set-cookie" from the response
if (urlConnection != null)
for (int i = 1;(key = urlConnection.getHeaderFieldKey(i)) != null; i++)
System.out.println(urlConnection1.getHeaderFieldKey(i) + ": " + urlConnection.getHeaderField(key));
if (key.equalsIgnoreCase("set-cookie"))
String cookiValue = urlConnection1.getHeaderField(key);
//How to set the cookie value in the subsequent requests
urlConnection2.setRequestProperty("Cookie", cookiValue);
Good luck.

How does it know to find demo helpsets under hsjar/ ?

Could not find a mention of "hsjar" yet when this directory name changes to something else, the demo does not find the help set.

sorry, found it, it is in the jar manifest

How does a session bean find entity beans in EJB 3.0

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