EJB 3.0 question - saving an entity bean containing another entity bean

Hi,
First, I want to store an entity bean. Secondly, I want to store another entity bean - containing the first entity bean.
I have the following code in a session bean for this:
public void saveFeedScheduling(FeedScheduling feedScheduling, FeedSource feedSource) {
FeedSource feeds = em.merge(feedSource);
em.flush();
feedScheduling.setFeedSource(feeds);
FeedScheduling feedSched = em.merge(feedScheduling);
em.flush();
This seems to work fine - still, is this the proper way to do it?

Hello,
This kind of parameter can be specified using the relationship annotation.
I'm not 100% sure, but, lok at the "cascade element".
Regards,
Sebastien Degardin

Similar Messages

How to use a session bean in another session bean (or an EJB in a session)

JDev 11.1.1.4, WLS 10.3.4, Windows 7 x64
I have a login controller with a session-scoped bean that manages logins.
I have another session-scoped bean that manages menu security.
both modules compile and work fine now I need to share the data from one to another.
I need to reference the login controller in the menu security bean. How do I reference (include) the login bean in the security bean?
I tried an EJB - what a farce - these are supposed to be universal and easy ( basis of the oop in Java).
the bean is defined:
@Stateless(name = "SecurityEJB", mappedName = "ZITASApplication-ZITASModel-SecurityEJB")
I have tried :
ic = new InitialContext();
session = (SecurityEJBLocal)ic.lookup("ZITASApplication-ZITASModel-SecurityEJB#model.security.logic.SecurityEJB");
session = (SecurityEJBLocal)ic.lookup("ZITASApplication-ZITASModel-SecurityEJB#model.security.logic.SecurityEJBLocal");
session = (SecurityEJBLocal)ic.lookup("java:ejb/model.security.logic.SecurityEJB");
session = (SecurityEJBLocal)ic.lookup("java:ejb/SecurityEJB");
session = (SecurityEJBLocal)ic.lookup("java:app/SecurityEJB");
session = (SecurityEJBLocal)ic.lookup("java:module/SecurityEJB");
All return null pointers and claim the name cannot be resolved.
As you can see - I have found various claims to how to do this.
One way says create a sevlet, generate a listener and use the sevlet. Basically one for every EJB - a lot of work to use the EJBs
I would assume that this would be one of the easiest parts of java - as it is the foundation of re-usability and oop.
I can do either in the application - the added complexity of the EJB is less desirable - but better programming?

Hi,
ic.lookup("ZITASApplication-ZITASModel-SecurityEJB#model.security.logic.SecurityEJB");This should work with remote interface. If you want to lookup local interface, you need to register it in web.xml. Quote:
To access the business local interface you need to define ejb local references for your component environment (i.e. from your servlet environment). You can do this by defining references in your web.xml. For example:
<ejb-local-ref>
<ejb-ref-name>ejb/BusinessLogicBean</ejb-ref-name>
<local>packagename.BusinessLogicBean</local>
</ejb-local-ref>
To lookup your local reference from your servlet you need to use the following JNDI reference:
java:comp/env/ejb/BusinessLogicBean Another one
First, declare a local ejb reference in your web.xml file (This will add it to JNDI):
<ejb-local-ref>
<ejb-ref-name>ejb/Foo</ejb-ref-name>
<local>simple.ejb.FooLocal</local>
</ejb-local-ref>
Then it can be looked up from JNDI:
InitialContext ctx = new InitialContext();
FooLocal foo = ctx.lookup("java:comp/env/ejb/Foo");Hope this helps.
Pedja
Helpful links (judging from your first post, you are probably sick of these :) )
How to lookup local EJB in Oracle Weblogic 10.3
http://m-button.blogspot.com/2008/07/reminder-on-how-to-use-ejb3-with.html
http://www.coderanch.com/t/451012/EJB-JEE/java/EJB-Local-Lookup-not-working

Problem deploying cmp bean invoking another cmp bean using jndi lookup

I have a cmp BeanA that invokes another cmp BeanB, so I am using a jndi lookup in BeanA to download the localhome object to BeanB using the following:
Context ctx = new InitialContext();
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then I specify the ejb/BeanBHomeRef, entity bean, local, BeanB's local home and component interface in EJB ref. when I am packaging BeanA
I also package BeanB in a separate jar file.
When I attempt to deploy the application it throws strange exception that says the folowing:
java.lang.IllegalArgumentException: BeanBEJB says it links to an ejb called BeanBEJB of local home class LocalBeanBHome but no bean with this local home c
lassname and type can be found in this ejb-jar.
yet when I un-jar the package, these class files exitsts.
When I go ahead and delete the reference to BeanB from the BeanA package file, I am able to deploy the application but then correctly fails on jndi lookup.
I have been able to open the cmpcustomer.ear sample application that comes with RI and execute it without any problem. But when I to package the same beans for example CustomerBean and it won't even allow me to create the customer.jar file. I get a screen full of errors.......
I am using Sun RI 1.3.01, is there a known bug that I am not aware of? Is there a fix around it?
Is there any another way to get the home ref. to BeanB so I can invoke create() method?
Any advice or suggestions?
thanksl
-kaisaab

What app server are you using? may be I can help you
--Ashish Saraf

How do I use a managed bean in another managed bean

I have two managed beans. One is backing bean for a form and the other is used to access a database table.
1st bean
public class TestDBAO
@PersistenceContext
private EntityManager em;
public void addEntry(PersonObj person)
em.persist(person);
public class formdata
private String id;
private String fname;
private String lname;
getter functions
setter functions
public String submit()
in here i want to call addEntry function from TestDBAO
How can I achieve this or is there another way to do this?

Do I understand correctly that you have definied TestDBAO as a session scoped managed bean? Why?
You don't need that. Just create and call TestDBAO in the backing bean. Or if you want only one instance of TestDBAO during the session, then create a singleton constructor and eventually make the methods static.

Error calling Method on Managed Bean from another Managed Bean

Hi
(Jdev 11.1.1.2.0)
Help please:
I have a managed bean (page flow scope) which is used by my main page for dynamic region flow navigation:
*public class RegionNavigationBean implements Serializable{*+
private String dynamicTaskFlowId = "/WEB-INF/home-task-flow-definition.xml#home-task-flow-definition";+
*public RegionNavigationBean() {*+
*public TaskFlowId getDynamicTaskFlowId() {*+
return TaskFlowId.parse(dynamicTaskFlowId);+
*public void setDynamicTaskFlowId(String taskFlowId) {*+
this.dynamicTaskFlowId = taskFlowId;+
taskFlowId property on main page def is set to +*${pageFlowScope.regionNavigationBean.dynamicTaskFlowId}*+
In a DB table (i.e. View Object on my model layer) I store a menu ID and a corresponding task_flow_id.
Then I have created an action listener class (RegionNavigationListener - page flow scope) which I link to my menu items on my main page (action listener property on menu item = +*#{pageFlowScope.regionNavigationAction.processAction}*+ )
In this action listener (processAction method), I retrieve the row set from the menu VO and find the record which matches my menu ID which caused the action event, thereby retrieving the task_flow_id which must be navigated to.
I then try to retrieve the instance of the RegionNavigationBean with the following statement: RegionNavigationBean regNav = (RegionNavigationBean)JSFUtils.getManagedBeanValue("regionNavigationBean");+
This seems to work fine, but as soon as I try and use this I get NullPointerException error, e.g.:
regNav.setDynamicTaskFlowId(menusRow.gettaskFlowId());+
or even:
System.out.println("%%% " + regNav.toString());+
This is all quite new to me... any help would be appreciated!
Thanks
Mario

Hi Mario,
I think JSFUtils.getManagedBeanValue(String) has difficult to evaluate the "regionNavigationBean" managed bean.
What JSFUtils.getManagedBeanValue(String) do is important. I remember that "JSF scoped" bean can be found by JSF style find method, such as requestScope, sessionScope, applicationScope. For a managed bean put in these scope, scope prefix is not needed, for example: using #{beanName} to locate a requestScope bean. The #{requestScope} prefix is not needed.
But pageFlowScope is different. If a bean is put in the pageFlowScope, you must use #{pageFlowScope.beanName} to locate it.
Say, ManagedBean is the java class of your manged bean.
FacesContext ctx = FacesContext.getCurrentInstance();
Application app = ctx.getApplication();
ManagedBean mb = (ManagedBean)app.evaluateExpressionGet(ctx, "#{pageFlowScope.managedBeanName}", ManagedBean.class);
Hope it helps.
Todd
Edited by: Todd Bao on Nov 26, 2009 9:58 PM

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{
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//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

JavaBeans bean container

I have a JavaBean, where one of the properties of the bean is as a bean container for other beans of a certain type or sub-type. I would like to specify this property as a BeanContext, which is the traditional bean container under Java 1.4 and up. While I can specify the type of this property as a BeanContext, and instantiate a BeanContext from the BeanContextSupport class, how can I get IDE environments which host JavaBeans to generically treat this property as a nested BeanContext ?

Hi
i had the same doubt!
i found this link
http://forum.java.sun.com/thread.jspa?threadID=787649&start=10&tstart=0
hope it helps!!
Regards!!!
Tiago

EJB 3.0 Session bean transfers null Entity

Hello all
I am having trouble trying to transfer an Entity from a stateful session bean to a JSP. When I try an identical method with a java client within the OC4J container of JDeveloper, it works fine. However when I deploy the application to OracleAS 10.1.3, I get a null pointer on the entity.
Please help. I have been stuck on this for about 3 weeks, and I've followed documentation to the letter as far as I can see.
Here is the code for the JSP, the (simplified) bean and the Entity in question.
Bean:
import java.util.List;
import javax.annotation.Resource;
import javax.ejb.Stateful;
import javax.persistence.EntityManager;
import javax.persistence.Query;
@Stateful(name="cart")
public class CartBean implements CartRemote, CartLocal {
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    protected EntityManager manager;
    public CartBean() {
         public User getUser(String username){
                User user = manager.find(User.class, username);
         return user;
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<%@ page contentType="text/html;charset=windows-1252"%>
<%@ page import="com.evotec.ereq.CartLocal" %>
<%@ page import="com.evotec.ereq.User" %>
<%@ page import="javax.naming.InitialContext" %>
<%@ page import="java.util.List" %>
<%@ page import="java.util.ArrayList" %>
<%!String m_username = "pbarrett";%>
<%!String emailAddress = "";%>
<%
try {
    InitialContext ctx = new InitialContext();
    CartLocal cart = (CartLocal) ctx.lookup("java:comp/env/cart");
        User user = cart.getUser(m_username);
        emailAddress = user.getEmailAddress();
%>
<html>
<body>
you are: <%= m_username %><BR>
your email address is: <%= emailAddress %><BR>
</body>
</html>
<%
catch (Exception e){
    e.printStackTrace();
%>and the User entity:
import java.io.Serializable;
import java.sql.Timestamp;
import static javax.persistence.AccessType.FIELD;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Table;
import javax.persistence.Id;
@Entity(access=FIELD)
@Table(name="USERS")
public class User implements Serializable {
    @Column(name="CREATION_DATE")
    protected Timestamp creationDate;
    @Column(name="DISPLAY_NAME")
    protected String displayName;
    @Column(name="EMAIL_ADDRESS")
    protected String emailAddress;
    @Id
    @Column(name="USERNAME")
    protected String username;
    @Column(name="USER_ID")
    protected Long userId;
    @Column(name="USER_STATUS")
    protected Long userStatus;
    public User() {
          //JDeveloper-generated getters and setters
}I should point out that I have established that the null pointer is not coming from the CartLocal lookup.
Any help welcome, thanks in advance.
Paul

Hi,
Thanks for the quick response.
I have tried this approach before but when I try and deploy to the server, I get this message:
@PersistenceContext annotation can only be used when a javax.spi.PersistenceProvider is installed.
Is this a missing jar file? If so, which one?
Thanks
Paul

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.

Do JNDI look up for entity beans from a session bean in different jars

I have a problem doing entity beans JNDI look up from a session bean which is deployed
as a separate package (session.jar) from the entity beans (entity.jar)
I believe if both session bean and entity beans are deployed into one jar and
I specify ejb-local-reference-description for session bean, it should work. However,
due to some reason, they have to be in separated packages but still in the same
container. Then question how to do JNDI lookup given entity beans only have local
interfaces?
FYI.
1 both session.jar and entity.jar are self-contained. i.e., no deployment error.
each JNDI name can be viewed from JNDI tree
2. weblogic-ejb-jar.xml for session.jar
<weblogic-ejb-jar>
<description><![CDATA[Generated by XDoclet]]></description>
<weblogic-enterprise-bean>
<ejb-name>PetstoreLogic</ejb-name>
<stateless-session-descriptor>
</stateless-session-descriptor>
<reference-descriptor>
</reference-descriptor>
<jndi-name>PetstoreLogic</jndi-name>
<local-jndi-name>PetstoreLogicLocal</local-jndi-name>
</weblogic-enterprise-bean>
</weblogic-ejb-jar>
3. weblogic-ejb-jar.xml (code snip) for entity.jar
<weblogic-enterprise-bean>
<ejb-name>Account</ejb-name>
<entity-descriptor>
<persistence>
<persistence-type>
<type-identifier>WebLogic_CMP_RDBMS</type-identifier>
<type-version>6.0</type-version>
<type-storage>META-INF/weblogic-cmp-rdbms-jar.xml</type-storage>
</persistence-type>
<persistence-use>
<type-identifier>WebLogic_CMP_RDBMS</type-identifier>
<type-version>6.0</type-version>
</persistence-use>
</persistence>
</entity-descriptor>
<reference-descriptor>
</reference-descriptor>
<local-jndi-name>net.sourceforge.cpetstore/AccountLocalHome</local-jndi-name>
</weblogic-enterprise-bean>
4. if I do
accountLocalHome = (AccountLocalHome) ic.lookup("net/sourceforge/cpetstore/AccountLocalHome");
get error like:
javax.naming.LinkException: . Root exception is javax.naming.NameNotFoundException:
While trying to look up /app/ejb/net.sourceforge.cpetstore-entity.jar#Account/local-home
in /app/ejb/cpetstore-ejb.jar#PetstoreLogic.; remaining name '/app/ejb/net/sourceforge/cpetstore-entity/jar#Account/local-home'
     at weblogic.jndi.internal.BasicNamingNode.newNameNotFoundException(BasicNamingNode.java:869)
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In weblogic-ejb-jar.xml use jndi-name instead of local-jndi-name in reference-descriptor
element.
"Qiming He" <[email protected]> wrote:
>
I have a problem doing entity beans JNDI look up from a session bean
which is deployed
as a separate package (session.jar) from the entity beans (entity.jar)
I believe if both session bean and entity beans are deployed into one
jar and
I specify ejb-local-reference-description for session bean, it should
work. However,
due to some reason, they have to be in separated packages but still in
the same
container. Then question how to do JNDI lookup given entity beans only
have local
interfaces?
FYI.
1 both session.jar and entity.jar are self-contained. i.e., no deployment
error.
each JNDI name can be viewed from JNDI tree
2. weblogic-ejb-jar.xml for session.jar
<weblogic-ejb-jar>
<description><![CDATA[Generated by XDoclet]]></description>
<weblogic-enterprise-bean>
<ejb-name>PetstoreLogic</ejb-name>
<stateless-session-descriptor>
</stateless-session-descriptor>
<reference-descriptor>
</reference-descriptor>
<jndi-name>PetstoreLogic</jndi-name>
<local-jndi-name>PetstoreLogicLocal</local-jndi-name>
</weblogic-enterprise-bean>
</weblogic-ejb-jar>
3. weblogic-ejb-jar.xml (code snip) for entity.jar
<weblogic-enterprise-bean>
<ejb-name>Account</ejb-name>
<entity-descriptor>
<persistence>
<persistence-type>
<type-identifier>WebLogic_CMP_RDBMS</type-identifier>
<type-version>6.0</type-version>
<type-storage>META-INF/weblogic-cmp-rdbms-jar.xml</type-storage>
</persistence-type>
<persistence-use>
<type-identifier>WebLogic_CMP_RDBMS</type-identifier>
<type-version>6.0</type-version>
</persistence-use>
</persistence>
</entity-descriptor>
<reference-descriptor>
</reference-descriptor>
<local-jndi-name>net.sourceforge.cpetstore/AccountLocalHome</local-jndi-name>
</weblogic-enterprise-bean>
4. if I do
accountLocalHome = (AccountLocalHome) ic.lookup("net/sourceforge/cpetstore/AccountLocalHome");
get error like:
javax.naming.LinkException: . Root exception is javax.naming.NameNotFoundException:
While trying to look up /app/ejb/net.sourceforge.cpetstore-entity.jar#Account/local-home
in /app/ejb/cpetstore-ejb.jar#PetstoreLogic.; remaining name '/app/ejb/net/sourceforge/cpetstore-entity/jar#Account/local-home'
     at weblogic.jndi.internal.BasicNamingNode.newNameNotFoundException(BasicNamingNode.java:869)
     at weblogic.jndi.internal.ApplicationNamingNode.lookup(ApplicationNamingNode.java:150)
     at weblogic.jndi.internal.WLContextImpl.lookup(WLContextImpl.java:338)

Can CMT Session Bean call BMP Entity Bean in WebLogic 6.0?

          Hi
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          --Winston
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          E
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          [java.rmi.NoSuchObjectException: Exception from ejbStore:javax.ejb.NoSuchEntityE
          xception: ejbStore: AccountBean (4003) not updated]],numRepliesOwedMe=0,numRepli
          esOwedOthers=0,seconds since begin=0,seconds left=30,SCInfo[examplesServer]=(sta
          te=rolledback),properties=({weblogic.transaction.name=[EJB TraderBeanImpl.buy()]
          })): java.rmi.NoSuchObjectException: Exception from ejbStore:javax.ejb.NoSuchEnt
          ityException: ejbStore: AccountBean (4003) not updated
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          meUtils.java:57)
          at weblogic.ejb20.manager.DBManager.beforeCompletion(DBManager.java:364)
          at weblogic.ejb20.internal.TxManager$TxListener.beforeCompletion(TxManag
          er.java:211)
          at weblogic.transaction.internal.ServerSCInfo.callBeforeCompletions(Serv
          erSCInfo.java:511)
          at weblogic.transaction.internal.ServerSCInfo.startPrePrepareAndChain(Se
          rverSCInfo.java:78)
          at weblogic.transaction.internal.ServerTransactionImpl.localPrePrepareAn
          dChain(ServerTransactionImpl.java:893)
          at weblogic.transaction.internal.ServerTransactionImpl.globalPrePrepare(
          ServerTransactionImpl.java:1229)
          at weblogic.transaction.internal.ServerTransactionImpl.commit(ServerTran
          sactionImpl.java:168)
          at weblogic.ejb20.internal.BaseEJBObject.postInvoke(BaseEJBObject.java:2
          01)
          at examples.ejb.basic.statefulSession.TraderBeanEOImpl.buy(TraderBeanEOI
          mpl.java:37)
          at examples.ejb.basic.statefulSession.TraderBeanEOImpl_WLSkel.invoke(Tra
          derBeanEOImpl_WLSkel.java:76)
          at weblogic.rmi.internal.BasicServerAdapter.invoke(BasicServerAdapter.ja
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          at weblogic.rmi.internal.BasicRequestHandler.handleRequest(BasicRequestH
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          at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120)
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          at weblogic.transaction.internal.ServerSCInfo.startPrePrepareAndChain(Se
          rverSCInfo.java:78)
          at weblogic.transaction.internal.ServerTransactionImpl.localPrePrepareAn
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          at weblogic.transaction.internal.ServerTransactionImpl.globalPrePrepare(
          ServerTransactionImpl.java:1229)
          at weblogic.transaction.internal.ServerTransactionImpl.commit(ServerTran
          sactionImpl.java:168)
          at weblogic.ejb20.internal.BaseEJBObject.postInvoke(BaseEJBObject.java:2
          01)
          at examples.ejb.basic.statefulSession.TraderBeanEOImpl.buy(TraderBeanEOI
          mpl.java:37)
          at examples.ejb.basic.statefulSession.TraderBeanEOImpl_WLSkel.invoke(Tra
          derBeanEOImpl_WLSkel.java:76)
          at weblogic.rmi.internal.BasicServerAdapter.invoke(BasicServerAdapter.ja
          va:373)
          at weblogic.rmi.internal.BasicServerAdapter.invoke(BasicServerAdapter.ja
          va:237)
          at weblogic.rmi.internal.BasicRequestHandler.handleRequest(BasicRequestH
          andler.java:118)
          at weblogic.rmi.internal.BasicExecuteRequest.execute(BasicExecuteRequest
          .java:17)
          at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:137)
          at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120)
          --------------- nested within: ------------------
          weblogic.transaction.RollbackException: Unexpected exception in beforeCompletion
          : sync = weblogic.ejb20.internal.TxManager$TxListener@356eb0
          Error writing from beforeCompletion - with nested exception:
          [weblogic.utils.NestedRuntimeException: Error writing from beforeCompletion -
          wi
          th nested exception:
          [java.rmi.NoSuchObjectException: Exception from ejbStore:javax.ejb.NoSuchEntityE
          xception: ejbStore: AccountBean (4003) not updated]]
          at weblogic.transaction.internal.TransactionImpl.throwRollbackException(
          TransactionImpl.java:1261)
          at weblogic.transaction.internal.ServerTransactionImpl.commit(ServerTran
          sactionImpl.java:218)
          at weblogic.ejb20.internal.BaseEJBObject.postInvoke(BaseEJBObject.java:2
          01)
          at examples.ejb.basic.statefulSession.TraderBeanEOImpl.buy(TraderBeanEOI
          mpl.java:37)
          at examples.ejb.basic.statefulSession.TraderBeanEOImpl_WLSkel.invoke(Tra
          derBeanEOImpl_WLSkel.java:76)
          at weblogic.rmi.internal.BasicServerAdapter.invoke(BasicServerAdapter.ja
          va:373)
          at weblogic.rmi.internal.BasicServerAdapter.invoke(BasicServerAdapter.ja
          va:237)
          at weblogic.rmi.internal.BasicRequestHandler.handleRequest(BasicRequestH
          andler.java:118)
          at weblogic.rmi.internal.BasicExecuteRequest.execute(BasicExecuteRequest
          .java:17)
          at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:137)
          at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:120)
          >"


We did receive a 4.5.1 / 5.1 interoperability patch - but it wasn't quite 'seamless'.
We never tried to use it.
SOAP? Isn't that around 50 times slower than RMI?
Mike
"Gary Mui" <[email protected]> wrote:
We ran into this issue last fall and got some feedback from weblogic
support. They originally said that it could be done (as well as different
versions talking to one another via JMS) but it turned out that they
were
incorrect and ended up saying that it is not possible. Before 6.0 went
GA,
BEA said that there would be a interoperability patch to do this, but
I've
never seen nor heard of anything regarding it. As a workaround, we
implemented 4.5.1 / 6.0 communication via SOAP.
Mike Reiche wrote in message <3b1bcaec$[email protected]>...
I have the same question - and more. Last year we were told that wecould
not use
RMI (and ejbs) between 4.5.1 and 5.1. Which seems kinda weird becauseI've
heard
of people using WL ejbs from Tomcat. This issue has caused us to avoidusing
WL ejbs in any future development which has any chance of ever beingused
by any
app server (WL included) that is not under the direct control of thedata
center.
I've been trying to convince the Architecture team here that we canuse WL
EJBs
and we can call them from other app servers - but can't seem to getany
supporting
statement from BEA (maybe I haven't tried hard enough).
Anyway, a response from BEA would be appreciated.
- Mike
"Madhu K" <[email protected]> wrote:
Is it possible to call a (stateless session) bean deployed in weblogic
6.0
from a bean in weblogic 5.1? I have two versions of weblogic running
on two
different hosts and I have to call a bean that is running in 6.0 from
5.1.
Are there any limitations?
Appreciate any feedback/suggestions.
Thanks,
Madhu

EJB multiple choice question

1)The run() method gets invoked when the thread's start() method is invoked.Once invoked, the run() method will execute until which of the following run() termination conditions occur?
A      The interrupt() method is called or run() terminates naturally.
B      An external event that causes the JVM to terminate occurs or run() exits.
C      Either run() terminates or the stop() method is called.
D      The suspend() method is called.
E      The end() method is called.
Answer :
2) What must accompany a variable definition in order to ensure that the variable is scoped locally?
A      Nothing, there is no way to scope JavaScript variables.
B      Local
C      Var
D      Nothing, variables are always scoped locally by default.
E      Script tags
Answer:
3) What is the simplest way to associate a BeanInfo class with a bean class called MyBean?
A      The bean must implement the java.beans.getBeanInfo() method, which returns a BeanInfo object.
B      Name the BeanInfo class MyBeanBeanInfo.
C      The bean should implement the HasBeanInfo marker interface.
D      Use the Introspector.setBeanInfoSearchPath() method to specify the BeanInfo class.
E      Name the BeanInfo class MyBeanInfo.
Answer:
4)What objects are used as keys to store and retrieve objects bound to HTTP sessions?
A      Any object.
B      Any object of type SessionKey.
C      The string name of the servlet.
D      Strings.
E      Any class that implements javax.servlet.Servlet.
Answer:
5)What is the SessionSynchronization interface used for?
A      It is used to guarantee that all access to the bean will be performed within a transaction.
B      It forces the developer to write code that interacts with the container's transaction processing.
C      It allows a stateless session bean to temporarily behave like a stateful session bean.
D      It synchronizes the method calls of a stateful session bean so they will be called synchronously instead of asynchronously.
E      It is used to store user's state information between accesses of the methods of a stateful session bean.
F      It allows a session bean to be notified of transactional boundaries by its container.
Answer:
6)How can a ejb get the security identity of the client invoking the bean's methods?
A      There is no way for the bean to determine the caller's identity.
B      Use the EJBContext's getCallerIdentity() method.
C      The bean must perform a lookup in the Access Control List using the client's primary ID.
D      The SessionGroup object keeps a Vector off all currently active clients and is accessible through the EJBContext interface.
E      Call the EJBObject's getClientIdentity() method.
F      The caller's identity is automatically passed to the EJB and is accessible through the getClient() method.
Answer:
7)How are the fields in a container managed entity bean mapped to the appropriate fields in the database?
A      The entity bean's fields must have the same name as the database's fields.
B      The container creates fields in the database automatically to match the field names of the bean.
C      The deployment descriptor of the container allows the developer to create the mapping.
D      The container performs a metadata lookup on the database and matches types and names to the entity bean.
E      The developer creates a java.util.Properties file with the name/value pairs to match the field names to the database.
F      It is not necessary to map the fields of a entity bean into a database.
Answer
8)The developer is creating container managed entity beans to map to records in a database. For this type of bean, what service(s) does the ejbCreate() method perform?
A      The ejbCreate() method restores passivated resources.
B      The ejbCreate() method creates a new bean instance.
C      The ejbCreate() method creates a new record in the database and returns it to the ejbHome object.
D      The ejbCreate() method initializes a bean instance and creates a new record in the database.
E      The ejbCreate() method returns true if a matching record can be found and an object instantiated or false otherwise.
F      The ejbCreate() method associates a pooled bean instance with a database record.
Answer:
9)Which types of beans can be pooled by the container?
A      Only Entity beans.
B      All beans can be pooled.
C      Only stateful session beans.
D      Only stateless session beans.
E      Any session bean that implements the "Poolable" interface.
F      Only Session beans.
Answer:
10) How can a servlet notify a client that a requested resource has moved to a different URL?
A      Throw a javax.servlet.UnavailableException.
B      Send a JavaScript code fragment to the client that loads the new location.
C      Throw a javax.servlet.ResourceMovedException.
D      Call HttpServletResponse.sendRedirect() with the URL of the new location.
E      Return -1 from the servlet service method.
Answer:

Hi Mr
This is not a certification questions. It doesn't matter whatever these questions are. Homework, certification, other.
It does not matter. Same advice applies.
i would like to check with my answers.But you haven't given any answers.

Finder method in container-managed entity bean

Finder method of a container entity bean is taking the primary key class object of another entity bean. How to map this in the xml descriptor file weblogic-cmp-rdbms.xml for this type of beans.
I am trying to deploy the jasmine computer store of Mastering EJB by EdRoman.
I couldn't write the deployment file weblogic-cmp-rdbms.xml for Order Entity bean which uses CustomerPK as an argument in its finder method.
Please tell me how to write this. I am trying on weblogic 5.1
Thanx in advance
Srivatsa

hello,
in container managed persistence, you specify on your xml file the name of your table. so the primary key you want to use have to be a foreign key in your table. otherwise i don't think that you can use a container managed persistence.
Najib.

Container Managed Entity Beans and Client Identifier in Oracle

Is it possible to use Container Managed Entity Beans (EJB with CMP)
in a way that the Oracle database sessions still know the
individual Client Identifiers of the actual users
(not just the Identifier of the proxy user defined in the
Connection Pool)?
If Yes: How?
If No: The consequence would be that the
technologies EJB with CMP cannot be user together with
Oracle Virtual Private Databases (VPN) because VPN requires
some kind of Client Identifier.
I am grateful for any hint.
Regards,
Martin Siepmann
+49 (0)163 / 7765328

Not quite an auto-incrementing PK, but it is managed by the container. the following is from the turorial
Generating Primary Key Values
For some entity beans, the value of a primary key has a meaning for the business entity. For example, in an entity bean that represents a phone call to a support center, the primary key might include a time stamp that indicates when the call was received. But for other beans, the key's value is arbitrary--provided that it's unique. With container-managed persistence, these key values can be generated automatically by the EJB container. To take advantage of this feature, an entity bean must meet these requirements:
* In the deployment descriptor, the primary key class is defined as a java.lang.Object. The primary key field is not specified.
* In the home interface, the argument of the findByPrimaryKey method must be a java.lang.Object.
* In the entity bean class, the return type of the ejbCreate method must be a java.lang.Object.
In these entity beans, the primary key values are in an internal field that only the EJB container can access. You cannot associate the primary key with a persistent field or any other instance variable. However, you can fetch the bean's primary key by invoking the getPrimaryKey method, and you can locate the bean by invoking its findByPrimaryKey method.
Maybe that is good enough
christina

Best Practice EJB 3.0 Question

I have a web application consisting of 3 projects:
- Model (EJB 3.0 Session Beans connected to two different databases)
- TagLibrary (custom tag library)
- ViewController (Web App / GUI)
Currently I am connecting to the EJB Beans using code that Jdeveloper generates for a test client:
env.put( Context.INITIAL_CONTEXT_FACTORY, "weblogic.jndi.WLInitialContextFactory" );
env.put(Context.PROVIDER_URL, "t3://localhost:7101");
However would like to move these to a properties file (I believe jndi.properties) such that they can be modified based on app server.
My question is following:
What is best practice for Session beans in the Model project to access other session beans in the same project? Do I also need to specify JNDI prop file and settings? (This occurs when Bean from one database needs to access bean from another database).
Or should I really put these in two separate projects / EJB libraries?
Thanks,
Kris

You have two options, first is to use JNDI lookup (you should be able to use just new InitialContext(), without the environment map).
Second one is more elegant and, as far as I'm concerned, should be referred to as best practice, that is using dependency injection:
@EJB
YourSesionBeanInterface yourEJB;
If you get stuck, there is plenty of documentation about this on the internet.
Pedja

EJB 3.0 question - saving an entity bean containing another entity bean

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