Javabeans and EJB

hi
I am new to EJB and i have not worked on javabeans...
My question is very basic... what is the difference between javabeans and EJB other than EJB running on a container and javabeans in jvm?
Thanks for your help

That's it in a nutshell, isn't it? EJBs require a J2EE container, and JavaBeans are components that follow the JavaBeans spec and run in a JVM.
But think about all that the "container" means and all the services it provides. That's all the difference in the world.
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Similar Messages

What is relationship between javabeans and Ejb ?

I am new to javabeans and Ejb .
thanks in advance.
zzl_hz_cn

nada. null. nil. void. zero. zilch.

What is the diffrence between a javabean and EJB

hi!
what is the diffrence between a javabean and entreprise jvaabeans! i mean which are the uitilization featires of eaxh one !

i am seeking for a solution for my problem , in fact i ma trying to implement and develop an application with java that allows a certain range of IP adresses to be connected to a database server in order to extract the suitable data from the server .
let me explain mor ethe suitation , in fact what i am loking for is to use javabeans to grant my application much more consistence and pertinence : si i am asking if it could be possible to use javabeans in my case especially if i am not trying to developp a web application but a cleint /server one allowing some services.
The application is in fact dealing with a stock exchange market and what i am trying to do is to grant particilar registrated customers to have the informations that they need ( portofolio, currency's status, market indicators, .) also drawing some charts decribing rates, variations, and others specefic financial caracterestics .So , if we consider that this application is not a web application ( no HTTP request and no servers like apache or others ) how it is possible to use javabeans and not EJB to build the application? i mean what could be suitable and preferable to rely on and dvelop to ensure a good java application !!
if you need more details to help you find the answer for me don't hesitate to answer me back !!
Someone here gave me that answer
use RMI to code the services and (Updateable) Value Objects to pass the information between tiers.
RMI is an all-java distributed component framework (ie. EJB, CORBA, DCE/RPC, DCOM, etc.), that is very suitable for developing non-containerized multi-tier applications. Refer to the RMI trail in the Java Tutorial as a starting point for coding RMI solutions (http://java.sun.com/docs/books/tutorial/index.html). Under this scenario you would code the database access service as an RMI service (server-side). Client/server communication should be facilitated through the use of JavaBeans/classes that wrap the information being passed (customer information, portfolio details, market information, etc.) - these are refered to as 'Updateable Value Objects' (a design pattern). Graphing and charting would be handled in your client from the information received from the (RMI) server. GUI JavaBeans can be used to provide this functionality as well as other client-side services. There are numerous "shrink-wrapped" components for GUIs available on the market just peruse any Java magazine to find them.
but how comes? how can i do it !! and where can i find more information please about 'Updateable Value Object "
thanks

JavaBeans and EJB Difference

Hi Experts:
Can anyone tell me DIFFERENCE between JAVABEANS and ENTERPRISE JAVABEANS? I am a newbie to JavaBean world. How do we know which one to use when?
Also, any startup BASIC TUTORIAL Link would be appreciated.
Thanks!

A javabean is simply a class that, through established conventions, exposes certain elements as standard properties. See http://developer.java.sun.com/developer/onlineTraining/Beans/beans01/ and http://developer.java.sun.com/developer/onlineTraining/Beans/beans02/ for a tutorial. Javabeans are a common part of most java programming.
An enterprise java bean (EJB) is a heavyweight, transactional, remotable component running in a managed "container." EJB has little or nothing to do with regular javabeans. Use EJBs to build web applications and web services with steep scalability, failover and transactional requirements. See http://www2.theserverside.com/books/masteringEJB/index.jsp for a lengthy and comprehensive tutorial.

What is the difference of using JavaBean and regular classes?

Experts,
I am new to JavaBean(not EJB), and wondering what is the difference of using JavaBean for JSP page compared with using regular Java class?
I know there are Bean tags which save some lines, what else?
What does "serialization" mean compared with "not serializable"?
thanks very much.

No.
A JavaBean is a regular JavaClass that:
1) implements java.io.Serializable
2) Its data members are private, and its data is accessed via getters and setters. You must define the getters and setters. Getters retrive the property, and must be in the format:
public PropertyType getPropertyName()
for most cases. The exception is when the PropertyType is a boolean, in which case you use:
public boolean isPropertyName()
Setters assign values to the property, and are in the form:
public void setPropertyName(PropertyType propValue)
3) There is also a PropertyChangeEvent model that needs to be followed.
A marker interface has no methods you need to implement. It just marks the class as supporting certain operations. In the case of Serializable, it means the class can be written to be an ObjectOutputStream for persistant storage.
As far as an example of JavaBean persistance, take a search on the java.sun.com site for Serializeable
Also, take a look at this: http://java.sun.com/developer/onlineTraining/Beans/beans02/
It concentrates mainly on gui component beans, but not all beans need to be gui parts... There are other pages to look at, but I can't find them at the moment, and I have to run...

JavaBeans in EJB App

In which circumstances to use JavaBeans in Ejb application?
I have created a simple e-commerce application using EJB components but without JavaBeans at all.
The thing is that i have a problem with the jsp page which presents all the products under a particular category, (each product has a link to add it to the shopping cart of the user).
After the user select a category, a servlet getting the products list from a session ejb and put the result as an attribute in the request. Then i'm prining all the products - till here no problem.
In order to add a product to the shopping cart i'm sending to a servlet some info about the product , but this info sometimes contains a special characters , so i decided to use <c:url> with <c:param> for the attributes.
     <%
      java.util.List<Entity.Products> products=(java.util.List<Entity.Products>)request.getAttribute("products");
       for(Entity.Products product : products)
        %>
<c:url value="ShoppingCartServlet" var="productUrl">
      <c:param name="productId" value="" />
      <c:param name="productName" value=""/>
</c:url>
<A href="${productUrl}">Add</A>now how can i set the values of the params?
i can't use scripting elements (<%=%>) , it is not allowed.
Do i need to use JavaBeans?
Thanks in advanced.

is it so hard? Looky here:
; hostname: 127.0.0.1; port: 3820"The application is trying to connect to the localhost, and the glassfish server is not running on the localhost. The JNDI properties of the application must point to the actual host that the glassfish server is running on.

Difference between simple beans and EJB

Anybody knows... the difference between the simple beans and EJB... Pls share with all. thanks a lot.

The Verrrrrrrrry short scoop is that JavaBeans pretty much just adhere to a standard format, mostly getters and setters. EJBs work only within a specific framework - an EJB container, and have access to J2EE support. For a detailed look at EJBs, see my tutorial Getting Started with Enterprise JavaBeans Technology at the developerWorks Java zone:
http://www-106.ibm.com/developerworks/edu/j-dw-java-gsejb-i.html
Joe Sam
Joe Sam Shirah - http://www.conceptgo.com
conceptGO - Consulting/Development/Outsourcing
Java Filter Forum: http://www.ibm.com/developerworks/java/
Just the JDBC FAQs: http://www.jguru.com/faq/JDBC
Going International? http://www.jguru.com/faq/I18N
Que Java400? http://www.jguru.com/faq/Java400

Jserver and EJB Scalability

Hi all,
I was wondering what other peoples expereinces with the scalability of EJBs and Jserver are. We are currently in development of a system that uses this technology, but have found that even the jndi lookup is slow.
Also we seem to be able to open only 8-10 iiop connections to the db(this is possibly a large_pool issue).
Lastly we are thinking about throwing BC4J(JBO) from Jdev3.1 into the mix and running them as EJBs but this is even slower.
I would appreciate any ones comments about these issues and fixes.
Thanks
Mark

Hi Mark. This is in answer to your email.
The large_pool setting is interesting. It depends on your bean size. I have a bean that takes up around 75K per session. So, depending on the number of sessions, I need to increase the large pool to be a multiple of 75K and the number of expected connections. Remember that the large_pool is only a portion of your shared_pool. This means that your large pool cannot be larger than your shared_pool. Also note, that the
large_pool defaults to 600K and that the java_pool is added to the overall total size of the SGA.
Do you know why we need the large pool? It is because the EJB service uses Multi threaded Server(MTS). The large pool stores all session information. Normally this is placed outside of the SGA in the PGA, however, once we use MTS, all that goes into the large_pool, and thus the need to size it properly.
Ahh, the number of connections is limited to the available free memory. Right now, I have sized my large pool to be around 2MB and that will allow for around 30 IIOP connections given my bean characteristics. So, you may find that you will have to add more memory if you are dealing with lots of connections. How many are you expecting?
Lastly, how an IIOP connection is made is interesting. If you use the standard lookup, it will create one connection per client application or calling application routine. IE. Using sess_sh will create one connection
per incarnation of this program. If you are using a threaded java application, using the standard lookup will result in one connection being used by all the threads. This may or may not be desirable. You would have to
open up named sessions for each thread. You can see an example of this in the JavaBeans and Corba developers guide, page 4-33 under the section Starting a Named Session from a client.
Starting multiple sessions is great sometimes. Oracle MTS will only allow so many sessions to be active. If you look at v$session and take not to the server column listed, you will see when that session is actually active. So, those connections are actually logical, as there are only so many MTS Servers that will do the actuall work. If you are severly hampered by memory issues, you may wish to create some sort of EJB
session name pool, however, this could get complex due to load balancing issues etc. I would recommend having Oracle's MTS take care of your connections for you, however this means more shared_pool/large_pool requirements.
Note on the JNDI Lookup. Yes, this is slow. So, I just perform the lookup once per session I am interested in creating, and always keep the reference to that object cached. So, yes it is slow using it the first time, after that, you get better performance. I would expect Oracle to come up with better performance as the product matures.
Good luck!
Brad
null

Diff b/w bc4j model and ejb model in adf11g

hi all,
iam murali iam new for adf 11g i have some dout's in adf11g ,can u please solve my probleam
what is the difference b/w bc4j componet and ejb componet,how to develop ejb application in adf11g.

,how to develop ejb application in adf11gTake a look at this tutorial for starters:
http://st-curriculum.oracle.com/obe/jdev/obe11jdev/ps1/ejb/ejb.html

JDBC, JMS and EJB transactions - possible problem?

Hello,
          I am using Oracle 9, Weblogic 8.1 SP 4, MyEclipse and
          XDoclet.
          In my current project I have the following piece of code
          in one of my message driven beans (code cited as pseudocode
          without unnecessary details):
          * @ejb.bean name="MyMessageProcessor"
          * display-name="Display name for a MyMessageProcessor"
          * jndi-name="ejb/MyMessageProcessor"
          * description="Bean MyMessageProcessor"
          * destination-type="javax.jms.Queue"
          * transaction-type="Container"
          * acknowledge-mode="Auto-acknowledge"
          * subscription-durability="Durable"
          * generate="false"
          * @ejb.transaction type="Required"
          public class MyMessageProcessor implements MessageDrivenBean, MessageListener {
          public void onMessage(Message msg) {
               try {
                    //obtaining connections to two different databases via JNDi
                    java.sql.Connection connOne =
                    ((DataSource)ctx.lookup("DataSourceOne")).getConnection();
                    java.sql.Connection connTwo =
                         ((DataSource)ctx.lookup("DataSourceTwo")).getConnection();
                    // performing some UPDATEs and INSERTs on connOne and connTwo
                    // calling some other methods of this bean
                    //creating the reply JMS message and sending it to another JMS queue
                    Message msgTwo = this.createReplyMessage(msg)
                    this.queueSender.send(msgTwo);
                    //commiting everything
                    this.queueSession.commit();
               } catch (Exception ex) {
               try {
                    if (this.queueSession!=null) this.queueSession.rollback();
               } catch (JMSException JMSEx) {};
               this.context.setRollbackOnly();
          Some days ago (before the final remarks from my client) there used to be only one DataSource configurated on the basis of the
          connection pool with non-XA jdbc driver. Everything worked fine
          including the transactions (if anything wrong happend not only wasn't the replymessage sent, but also no changes were written
          to database and the incomming message was thrown back to the my bean's
          queue).
          When I deployed the second DataSource I was informed by an error message, that only one non-transactional resource may
          participate in a global transaction. When I changed both datasources
          to depend on underlying datasources with transatcional (XA) jdbc drivers, everything stopped working. Even if
          EJB transaction was theoretically successfully rolledbacked, the changed were written to the database
          and the JMS message wasn't resent to the JMS queue.
          So here are my questions:
               1. How to configure connection pools to work in such situations? What JDBC drivers should I choose?
               Are there any global server configurations, which may influence this situation?
               2. Which jdbc drivers should I choose so that the container was able to rollback the database transactions
               (of course, if necessary)?
               3. Are there any JMS Queue settings, which would disable the container to send message back to the
               queue in case of setRollbackOnly()? How should be the Queue configurated?
          As I am new to the topic and the deadline for the project seems to be too close I would be grateful
          for any help.
          This message was sent to EJB list and JDBC list.
          Sincerely yours,
          Marcin Zakidalski

Hi,
          I found these information extremely useful and helpful.
          The seperate transaction for sending messages was, of course, unintentional. Thanks a lot.
          Anyway, I still have some problems. I have made some changes to the
          code cited in my previous mail. These changes included changing QueueSessions
          to non-transactional. I also set the "Honorate global transactions" to true.
          I am using XA JDBC driver. After setting "Enable local transactions" to false
          (I did it, because I assume that JDBC transactions should be part on the global
          EJB transaction) I got the following error:
          java.sql.SQLException: SQL operations are not allowed with no global transaction by default for XA drivers. If the XA
          driver supports performing SQL operations with no global transaction, explicitly allow it by setting
          "SupportsLocalTransaction" JDBC connection pool property to true. In this case, also remember to complete the local
          transaction before using the connection again for global transaction, else a XAER_OUTSIDE XAException may result. To
          complete a local transaction, you can either set auto commit to true or call Connection.commit() or Connection.rollback().
          I have also inspected the calls of methods of bean inside of onMessage() method just to check, whether
          the transactions are correctly initialized (using the weblogic.transaction.Transaction class).
          My questions are as follows:
          1. Any suggestions how to solve it? I have gone through the google answers on that problem and only
          thing I managed to realize that JDBC must start its own transaction. Is there any way to prohibit it
          from doing that? Can using setAutocommit(true/false) change the situation for better?
          2. How to encourage the JDBC driver to be a part of EJB transaction?
          3. As I have noticed each of ejb method has its own transactions (transactions have different
          Xid). Each method of the bean has "required" transaction attribute. Shouldn't it work in such
          way that if already started transaction exists it is used by the called method?
          4. The DataSources are obtained in my application via JNDI and in the destination environment I will have slight
          impact on the configuration of WebLogic. What is least problematic and most common WebLogic configuration which would
          enable JDBC driver to participate in the EJB transaction? Is it the WebLogic configuration problem or can it be
          solved programmically?
          Currently my module works quite fine when "enable local transactions" for DataSources is set to true, but this way
          I am loosing the ability to perform all actions in one transaction.
          Any suggestions / hints are more than welcomed. This message was posted to jdbc list and ejb list.
          Marcin

OC4J 9.0.3 and EJB 1.1 deployments???

I can not deploy my ejb1.1 beans on 9.0.3 container.
OC4J crashes with an XML parse error as a null pointer exception.
If I remove my O-R mappings from my orion-ejb-jar.xml file, the container starts up ok (app wont run as it needs the mappings)
9.0.3 docs claim I should be able to use my 1.1 ejb in this ejb 2.0 container.
Solaris release notes for 9.0.3 claim I must migrate to ejb2.0
Someone else posted this same question but got no replies.
Anyone else deployed ejb1.1 with OR mappings in 9.0.3 successfully yet?
thanks

I have tried migrating to an ejb2.0 set of beans and ejb-jar.xml file.
With no <query> tags installed for my finders I notice that a typical finder produces this:

This is vastly different from the 1.1 orion-ejb-jar.xml which would list ALL column names in the finder - hence how am I going to do a findAll? The currently generated sql is way off. Deployment of the "ormap" demo also shows a lack of column names in the generated SQL finder methods in orion-ejb-jar.xml.
Further, as soon as I introduce the query in the 2.0 version of ejb-jar.xml, the container dies with a null pointer exception. Removing this from the ejb-jar and bean deploys. Useless, cause theres no finders though.
Also, attempts to add to the <finder-method query=...> tag yield container crashes with null pointers too.
This is not very robust to say the least. Can you provide names of jar files that would cause such exceptions?
When NO query tag is inserted in the ejb-jar file, attempts to run a sample client using findByPrimaryKey return successfully but use of findAll causes timeouts similar to whats described in
"finders giving "timeout expired waiting for an instance" after 0, 1, or 2 calls" in this same forum.
Heres the query out of the ejb-jar.xml file...
<query>
<query-method>
<method-name>findAll</method-name>
<method-params></method-params>
</query-method>
<ejb-ql>
SELECT OBJECT(o) from IspTb o
</ejb-ql>
</query>
IspTb is the <abstract-schema-name> Tables exist in db.
The full error...which prevents deployment of the ejbs and hence no rewrite of the orion-ejb-jar file.
=========
10/23/02 1:54 PM: javax.ejb.EJBException: nested exception is: java.lang.NullPointerException
10/23/02 1:54 PM: java.lang.NullPointerException
10/23/02 1:54 PM: at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:274)
10/23/02 1:54 PM: at java.lang.ClassLoader.loadClass(ClassLoader.java:287)
10/23/02 1:54 PM: at com.evermind.naming.ContextClassLoader.loadClass(ContextClassLoader.java:135)
10/23/02 1:54 PM: at java.lang.ClassLoader.loadClass(ClassLoader.java:287)
10/23/02 1:54 PM: at com.evermind.naming.ContextClassLoader.loadClass(ContextClassLoader.java:135)
10/23/02 1:54 PM: at java.lang.ClassLoader.loadClass(ClassLoader.java:250)
10/23/02 1:54 PM: at com.sun.enterprise.deployment.PersistenceDescriptor.getClass(PersistenceDescriptor.java:767)
10/23/02 1:54 PM: at com.sun.enterprise.deployment.PersistenceDescriptor.getStateClass(PersistenceDescriptor.java:753)
10/23/02 1:54 PM: at com.sun.enterprise.deployment.PersistenceDescriptor.getCMPFieldType(PersistenceDescriptor.java:1302)
10/23/02 1:54 PM: at com.sun.enterprise.deployment.PersistenceDescriptor.initializeFieldInfo(PersistenceDescriptor.java:1052)
10/23/02 1:54 PM: at com.sun.enterprise.deployment.PersistenceDescriptor.getPersistentFieldInfo(PersistenceDescriptor.java:805)
10/23/02 1:54 PM: at com.sun.ejb.sqlgen.SQLGenerator.<init>(SQLGenerator.java:151)
10/23/02 1:54 PM: at com.sun.ejb.sqlgen.SQLGenerator.generateSQL(SQLGenerator.java:360)
10/23/02 1:54 PM: at com.sun.ejb.sqlgen.SQLGenerator.generateSQL(SQLGenerator.java:309)
10/23/02 1:54 PM: at com.evermind.server.ejb.deployment.EJBPackage.translateEjbqlQeries(EJBPackage.java:2100)
10/23/02 1:54 PM: at com.evermind.server.ejb.compilation.Compilation.translateEjbqlQeries(Compilation.java:140)
10/23/02 1:54 PM: at com.evermind.server.ejb.compilation.Compilation.compile(Compilation.java:178)
10/23/02 1:54 PM: at com.evermind.server.ejb.EJBContainer.postInit(EJBContainer.java:551)
10/23/02 1:54 PM: at com.evermind.server.Application.postInit(Application.java:431)
10/23/02 1:54 PM: at com.evermind.server.Application.setConfig(Application.java:136)
10/23/02 1:54 PM: at com.evermind.server.ApplicationServer.addApplication(ApplicationServer.java:1635)
10/23/02 1:54 PM: at com.evermind.server.ApplicationServer.initializeApplications(ApplicationServer.java:1585)
10/23/02 1:54 PM: at com.evermind.server.ApplicationServer.setConfig(ApplicationServer.java:1240)
10/23/02 1:54 PM: at com.evermind.server.ApplicationServerLauncher.run(ApplicationServerLauncher.java:93)
10/23/02 1:54 PM: at java.lang.Thread.run(Thread.java:479)
10/23/02 1:54 PM: javax.ejb.EJBException: nested exception is: java.lang.NullPointerException
10/23/02 1:54 PM: at com.sun.enterprise.deployment.PersistenceDescriptor.getClass(PersistenceDescriptor.java:770)
10/23/02 1:54 PM: at com.sun.enterprise.deployment.PersistenceDescriptor.getStateClass(PersistenceDescriptor.java:753)
10/23/02 1:54 PM: at com.sun.enterprise.deployment.PersistenceDescriptor.getCMPFieldType(PersistenceDescriptor.java:1302)
10/23/02 1:54 PM: at com.sun.enterprise.deployment.PersistenceDescriptor.initializeFieldInfo(PersistenceDescriptor.java:1052)
10/23/02 1:54 PM: at com.sun.enterprise.deployment.PersistenceDescriptor.getPersistentFieldInfo(PersistenceDescriptor.java:805)
10/23/02 1:54 PM: at com.sun.ejb.sqlgen.SQLGenerator.<init>(SQLGenerator.java:151)
10/23/02 1:54 PM: at com.sun.ejb.sqlgen.SQLGenerator.generateSQL(SQLGenerator.java:360)
10/23/02 1:54 PM: at com.sun.ejb.sqlgen.SQLGenerator.generateSQL(SQLGenerator.java:309)
10/23/02 1:54 PM: at com.evermind.server.ejb.deployment.EJBPackage.translateEjbqlQeries(EJBPackage.java:2100)
10/23/02 1:54 PM: at com.evermind.server.ejb.compilation.Compilation.translateEjbqlQeries(Compilation.java:140)
10/23/02 1:54 PM: at com.evermind.server.ejb.compilation.Compilation.compile(Compilation.java:178)
10/23/02 1:54 PM: at com.evermind.server.ejb.EJBContainer.postInit(EJBContainer.java:551)
10/23/02 1:54 PM: at com.evermind.server.Application.postInit(Application.java:431)
10/23/02 1:54 PM: at com.evermind.server.Application.setConfig(Application.java:136)
10/23/02 1:54 PM: at com.evermind.server.ApplicationServer.addApplication(ApplicationServer.java:1635)
10/23/02 1:54 PM: at com.evermind.server.ApplicationServer.initializeApplications(ApplicationServer.java:1585)
10/23/02 1:54 PM: at com.evermind.server.ApplicationServer.setConfig(ApplicationServer.java:1240)
10/23/02 1:54 PM: at com.evermind.server.ApplicationServerLauncher.run(ApplicationServerLauncher.java:93)
10/23/02 1:54 PM: at java.lang.Thread.run(Thread.java:479)

ABAP Objects and EJB

Hi every one,
Can <b>ABAP Objects and EJB</b> be compared?
-Naveen.

Hi Naveen,
Check this guide- might be useful-
https://www.sdn.sap.com/irj/servlet/prt/portal/prtroot/docs/library/uuid/dc09af90-0201-0010-d09b-bd611a11070b
Regards,
Moorthy

What is a javabean and how to compose it?

Q1:although have used many java class in jsp within tomcat, but i don't is it a standard javabean. I mean is any java class can be an javabean, or what is the different between javabean and java class.
for now i found some problem with 'javabean' used in jsp.
Q2:what is ther difference between use jsp:setProperty,jsp:getProperty and direct give value like 'myBean.variable=100'?
thanks!

javabeans are standard classes but have :
- default constructor
- getter and setter methods
javabean can be used on custom tags, so no code on your jsp !
why don't directly use attributes ?
look this thread :
http://forum.java.sun.com/thread.jsp?forum=45&thread=314643
this is one, but it's not the only, reason.
Regards.

Using SWING and EJB

Had nebody used Swing for GUI and EJBs for business logic. HEre i need to use Swing for gui rather than JSPs.
Can nebody help??

My question is ...
How do u call EJBs from swing based applets..
In J2EE transaction management cud be done at server side but how will we manage with the swing app??

OC4J EJBQL and EJB 2.0 features

Hello Debu Panda and All
I've got all howtos and I mangaged to get some parts of OC4J [Oracle9iAS (9.0.3.0.0) Containers for J2EE (build 020323.1689)] working.
There are still some issues that are stalling our development. Could you please comment on them, maybe providing an estimate of when they will be solved/implemented?
First of all, a little background. Our application uses many Java Swing application clients that connect to the EAR application in the container.
The ear application has the following structure:
All database access (Oracle 8i, located in its own server) is done exclusively by means of CMP entity beans. A entity bean may access other entity beans. There are workflow session beans (stateful and stateless) that access the entity beans. All clients see only the workflow session beans (session beans fagade).
Our applicatoin is complex, having more than 80 session beans and more than 25 entity beans (not counting entity beans that exist only to represent relationships among entity beans).
There goes the questions:
1) It seems that entity beans cannot currently be referenced by remote interfaces. We couldn't deploy our application using it. Since we could use only local interfaces fot entity beans, thats what is been done now.
2) There is no CMR supported. Is this true?
3) EJBQL seems to be very limited. In the howto examples there are EJBQL statements that compare two numbers. However, when we tried to use String comparisons, it didn't work. Here is the statement:
"SELECT DISTINCT OBJECT(p) FROM Person p WHERE p.name = ?1"
If I compile, package and deploy the ear applicatin with the above EJBQL statement, OC4J generates an exception when executing the finder method. The exception is:
"java.rmi.NoSuchObjectException: Session has timed out
at com.evermind.server.ejb.StatefulSessionEJBObject.throwPassivisat
ception(StatefulSessionEJBObject.java:188)
at Cad023Remote_StatefulSessionBeanWrapper0.obterPessoasPorParteNom
023Remote_StatefulSessionBeanWrapper0.java:754)
at java.lang.reflect.Method.invoke(Native Method)
at com.evermind.server.rmi.RMICallHandler.run(RMICallHandler.java:8
at com.evermind.util.ThreadPoolThread.run(ThreadPoolThread.java:64)"
If I remove the where clause, the expection is gone. However, I get all records. ;-)
4) It seems that all EJBQL clauses must be capitalized. Is this true?
FINALY)
Is there a newer OC4J build that could use to get the development going? Do you know where there will be one? Is there any way of contacting the OC4J development team to report bugs?
If you would like, we could discuss it in private e-mail (please use my private mail [email protected]).
Thanks for your attention,
Luis Fernando Soeiro
Hi !! OC4J 9.0.3 developer's preview has most features of EJB 2.0. We are working on updating on our docs and samples for EJB 2.0
Please look at the following URL that has some How Tos on EJB 2.0 features such Local Interfacea, EJB QL, etc : http://otn.oracle.com/tech/java/oc4j/htdocs/oc4j-how-to.html#ejb
regards
Debu Panda
Oracle --------------------------
Luis Soeiro <mailto:[email protected]> <mailto:[email protected]>Type : Question Date : Apr 11, 2002 15:15 PT Hello
Some colleagues and I are trying to port a large project from JBOSS to OC4J. We used JBOSS 3.0 (beta) in order to evaluate EJB2.0 features and see if we could use it. We already have OC4J in production, but only as a JSP/Servlet container. The next step would be to deploy our EJB application to OC4J.
We have read the material and it is written that OC4J (developers preview) is EJB 2.0 compliant. However, the specific documentation and the examples don't show how to specify OC4J specifc XML files. We absolutely need CMR and Local Interfaces, because we don't have the time required to downgrade our JBoss EJB2.0 application to the EJB 1.1 specification. We have over 80 Session Beans and over 20 Entity Beans.
Is there anybody there that can confirm that OC4J developer's preview is really EJB2.0 compliant? If so, could you send me some pointers to information about OC4J container specifc deployment descriptors? The docs listed at the web site don't have EJB2.0 features listed, nor does the Oracle samples.
Thanks for your attention,
desperately,
Luis Fernando Soeiro

HI,
I worked out CMR and EJB-QL with single bean.
Using CMR, it is possible to get one bean reference through other bean, but
When I tried EJB-QL with bean to bean navigation then I run into problem.

Javabeans and EJB

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