EJB beginner

hi all,
I want to learn EJB.
Can u tell me any knowledge require to learn EJB.
But i know servlets , JSP, java beans.
Plz....tell...me .....solutions...........

How to start EJB?Go purchase a book. If you are looking for some online material, download this e-book
http://www.theserverside.com/books/masteringEJB/index.jsp

Similar Messages

Learn about EJB ??

i'm a java developer and i want to learn, understand and work with EJB.
i'm looking for documents and links for ejb beginner.
thank you in advance

Did you try clicking on the Tutorials link on the upper left of this screen?

Beginner Question - Help Needed for EJB QL Sample Application

I'm working with a group of student interns, like myself, and we've been given an assignment to work with Oracle. All of us have no training or experience with this, so we're just learning as we go.
I've been trying to run the EJB QL Sample Application (http://www.oracle.com/technology/sample_code/tech/java/ejb_corba/ejbql/Install.html), but I keep running into problems at step 3.
Now, we will deploy the sample application onto OC4J. Open another command prompt and go to the folder <OC4J_HOME>/j2ee/home and run the following commands one-by-one
> java -jar admin.jar ormi://<machine_name>:<admin_port> admin <admin_pwd> -deploy -file <SAMPLE_HOME>/build/ejbql.ear -deploymentName Ejbql
> java -jar admin.jar ormi://<machine_name>:<admin_port> admin <admin_pwd> -bindWebApp Ejbql ejbql-war http-web-site /ejbql
where,
<machine_name>      Name of the machine where OC4J Server is running
<admin_port>      Admin Port on which the OC4J server listens. This value by default is 23791 unless explicitly changed by the user
<admin_pwd>      Adminstrator password to access OC4J. The default value is welcome
When I do this step I get this error:
Error: Unable to find java:comp/ServerAdministrator: Lookup error: javax.naming.
AuthenticationException: Invalid username/password for default (sds); nested exc
eption is:
javax.naming.AuthenticationException: Invalid username/password for defa
ult (sds)
com.evermind.client.orion.AdminCommandException: Unable to find java:comp/Server
Administrator: Lookup error: javax.naming.AuthenticationException: Invalid usern
ame/password for default (sds); nested exception is:
javax.naming.AuthenticationException: Invalid username/password for defa
ult (sds)
at com.evermind.client.orion.Oc4jAdminConsole.executeCommand(Oc4jAdminCo
nsole.java:105)
at com.evermind.client.orion.Oc4jAdminConsole.main(Oc4jAdminConsole.java
:27)
javax.naming.NamingException: Lookup error: javax.naming.AuthenticationException
: Invalid username/password for default (sds); nested exception is:
javax.naming.AuthenticationException: Invalid username/password for defa
ult (sds) [Root exception is javax.naming.AuthenticationException: Invalid usern
ame/password for default (sds)]
at com.evermind.server.rmi.RMIContext.lookup(RMIContext.java:153)
at com.evermind.client.orion.Oc4jAdminConsole.executeCommand(Oc4jAdminCo
nsole.java:102)
at com.evermind.client.orion.Oc4jAdminConsole.main(Oc4jAdminConsole.java
:27)
Caused by: javax.naming.AuthenticationException: Invalid username/password for d
efault (sds)
at com.evermind.server.rmi.RMIConnection.connect(RMIConnection.java:2410
at com.evermind.server.rmi.RMIConnection.connect(RMIConnection.java:2226
at com.evermind.server.rmi.RMIConnection.lookup(RMIConnection.java:1692)
at com.evermind.server.rmi.RMIServer.lookup(RMIServer.java:727)
at com.evermind.server.rmi.RMIContext.lookup(RMIContext.java:134)
... 2 more
---- Embedded exception
javax.naming.AuthenticationException: Invalid username/password for default (sds
at com.evermind.server.rmi.RMIConnection.connect(RMIConnection.java:2410
at com.evermind.server.rmi.RMIConnection.connect(RMIConnection.java:2226
at com.evermind.server.rmi.RMIConnection.lookup(RMIConnection.java:1692)
at com.evermind.server.rmi.RMIServer.lookup(RMIServer.java:727)
at com.evermind.server.rmi.RMIContext.lookup(RMIContext.java:134)
at com.evermind.client.orion.Oc4jAdminConsole.executeCommand(Oc4jAdminCo
nsole.java:102)
at com.evermind.client.orion.Oc4jAdminConsole.main(Oc4jAdminConsole.java
:27)
Any suggestions to fix this error?
Thanks in advance for any help.

George,
The Readme.html file is available with the ejbqlsample.jar downloadable (Extract and find the doc in Ejbql\docs\Readme.html) which is printable.
Or,
If you are trying to print the file directly from OTN site, you need to set the Page-Setup Orientation to 'Landscape'.
Hope this helps.
Regards
Pushkala

EJB 3.0 stateless bean + web client (beginner)

Hello,
I've just read the Sun tutorial on EJBs in Java EE 5 and I'm trying to get something nice and simple to work. My code is below:
Bank.java:
package beans;
import javax.ejb.Remote;
@Remote
public interface Bank {
     public void transfer(long source, long destination, long amount);
}BankBean.java:
package beans;
import javax.ejb.EJBException;
import javax.ejb.Stateless;
@Stateless
public class BankBean implements Bank {
     public void transfer(long source, long destination, long amount)
          System.out.println("This method is not yet implemented.");
          throw new EJBException("Method not implemented.");
}index.jsp (web project):
<%!
private Bank bank = null;
public void jspInit()
    try {
        InitialContext ic = new InitialContext();
        bank = (Bank) ic.lookup(Bank.class.getName());
    } catch (Exception ex) {
        System.out.println("Couldn't create bean." + ex.getMessage());
%>Everything compiles with no errors or warnings, but an exception is thrown. The message is "beans.Bank not found".
I have not modified any .xml files, I don't recall the tutorial saying I have to.
I'm using Eclipse 3.2 WTP and it doesn't recognize that I have any Session beans... not 100% sure that EJB 3.0 is supported by it. I ended up creating a basic Java project to store the beans because an EJB project was saying that I need at least one bean.
Thank you in advance for suggestions.
Pavel

While looking up why don't you use the fully
qualified jndi name"java:/comp/ejb...."?
What's the benefit of that?It's portable. Any direct access of a global JNDI namespace is not portable.
Also, it's "java:comp/env", not "java:/comp/env".
>
Is it possible to use annotations in JSPs?No, annotations are not supported in JSPs for Java EE 5. In the web tier
they can be used in certain managed classes such as servlets.
Regarding your original posting, how exactly did you deploy the ejb? If you
got a message saying the ejb-jar had no ejbs, that sounds like the root of
the problem. If the ejb-jar only contains a single EJB 3.0 bean and that
bean uses EJB 3.0 annotations instead of a deployment descriptor, make
sure there is no ejb-jar.xml. It's possible that Eclipse packaged an
EJB 2.1 - based ejb-jar.xml descriptor inside the ejb-jar. In that case,
the app server will assume it is an EJB 2.1 app and not process any
annotations.
--ken

* * * From a beginner in EJB * * *

I'm not a newbie programmer but all this stuff regarding EJB sometimes cause me a headache, you know.
I'm following "Enterprise JavaBeans Fundamentals" tutorial from developerWorks. You can reach this at IBM site. I've been reading a lot
of materials and until now this tutorial is the best I've ever found and
the examples work as expected.
Let's say I have an app with some EJBs (session (stateless and stateful) and entity beans), it doesn't matter what they do, I just have them. My question is about ejb-jar.xml file(s):
Do I need a deployment descriptor for each bean or I can have just only one in which I have all information about the beans ???
My best regards,
Romualdo Rubens de Freitas.

Greetings,
Hi Tony,
Based on what you said "...a composite of objects...",
if I have a Customer bean and an Order bean, both of
them can be a single EJB with a single ejb-jar.xml
file, right ??? If so, suppose a customer can haveThey can be "singly composed" within their own jar files or "multiply composed" within the same jar file. The thing to keep in mind here is that 'ejb-jar' file is what is actually the "EJB" - it is what is ultimately "distributed" and used to assemble larger applications...
zero or more orders, how can I specify (in
ejb-jar.xml) that a customer is "linked" with an order
or an order is "linked" with a customer ???Depends on what exactly you are refering to... "bean linkage" or "data linkage". The latter most appropriately regards CMP/EJB-QL and, therefore, is specific to EJB 2.0 Entity Beans. The former, however, regards bean-to-bean (actually, any J2EE application component-to-bean ;), references and are common to all bean types in EJB 1.1 and later. Also called "EJB references", these would seem most relevant to the issue at hand... Regardless of how they are packaged (above), one bean(/component) must reference another through the same mechanism as other components and clients: by looking it (it's "Home object" ;) up in the naming service and calling a lifecycle method.
Note: The argument for "Local interface types" should be recognized here but with the following caveats: 1) local interfaces are available as of EJB 2.0 only; 2) local interfaces are NOT specific to "multiply composed" EJBs but have, in fact, as their only requirement that the inter-referencing components are co-located within the same VM instance; and, consequently, 3) local interfaces do not need to be "narrowed" (since they are not being tunneled through the server's communication protocol ;).
As with other components making co-located references, the real burden here is on the Deployer (as in the "role of" ;) who must make sure that all 'coded references' are linked to actual 'JNDI bindings' at deployment time. This, naturally, is done according to the server vendor's method of doing so ("RTFM").
Greetings to you, my friend,
Romualdo Rubens de Freitas.Regards,
Tony "Vee Schade" Cook

Beginner to EJB

hi, can anyone guide me how to create an simple EJB application with Eclipse & JBOSS? already i worked with jsp, tomcat, eclipse....please guide me some links (other than google search links).... step by step EJB applicaiton creation and run in jboss using ecplise...?
thanks for the great help

Hi
There is a good plugin for Eclipse to support creating EJB applications. called MyEclipse. Although it's not free product, you can try it for 30 days. Since it is currently the easiest tool to create j2ee app on eclipse it would be good for you.
you can download plugin from here:
http://www.myeclipseide.com/
Here you will find set of tutorials:
http://www.myeclipseide.com/module-htmlpages-display-pid-7.html
There is a tutorial to create basic EJB apps there, also deploying them on JBoss3.2
Regards
Marecki

Beginner's EJB Question

I've been going through the J2EE tutorial and generally understand how it works but I have a question about application clients. I get the general concept that a client uses JNDI to look up the environment entry to find an EJB. However, I think my question is "how does the JNDI entry get set in the application client's machine?" In a web client it makes sense to me because the JSP hits the server (and the server is where the JNDI entry is). On the application client the only way I can think that the entry gets there is through maybe a jar file created when the application is compiled on the app server. My guess is that that's packaged with the application client and each user who installs the application client has to put the jar in their classpath. Is that correct?
In a very much related question, I'm also wondering how the client calls methods on the enterprise beans. I assume that the jar files have some code in them that make a network connection to the app server. I just wanted to verify that my understanding of how this all works is correct.

I've been going through the J2EE tutorial and
generally understand how it works but I have a
question about application clients. I get the
general concept that a client uses JNDI to look up
the environment entry to find an EJB. However, I
think my question is "how does the JNDI entry get set
in the application client's machine?" In a web
client it makes sense to me because the JSP hits the
server (and the server is where the JNDI entry is).
On the application client the only way I can think
k that the entry gets there is through maybe a jar
file created when the application is compiled on the
app server. My guess is that that's packaged with
the application client and each user who installs the
application client has to put the jar in their
classpath. Is that correct?
Not really. JNDI binding exists on server only. When client does a lookup it connects to server's naming service (via remote call) and asks an object with specific JNDI name.
In a very much related question, I'm also wondering
how the client calls methods on the enterprise beans.
I assume that the jar files have some code in them
m that make a network connection to the app server.
I just wanted to verify that my understanding of how
w this all works is correct.
Yes, it's correct. Code that makes a network connection is called a stub (or client stub). For some app. servers (SUN AS) you need to generate stubs of EJB's and put them into clien't classpath. For others (JBoss) it's not required, because a stub can be downloaded from server.

Beginner entity EJB question.

Hi,
I am researching into whether to use JDO for my application.
I have read that polymorphism, inheritance and complex relations are absent from EJB's. Is this true? I am thinking that maybe the place where I have read this are biased towards JDO, which is why they have stated this, and would like to get a neutral opinion.
Also, I read at JDOCentral that The acceptance of the Java Community Process� (JCP) JSR 243, also known as JDO 2.0, is in jeopardy. The recent vote by the JCP Executive Committee in the so called Public Review Ballot resulted in 5 YES votes and 10 NO votes and 1 abstention. I am a little confused. I keep hearing that JDO is so good, if that is the case, why was it rejected?
You see, I am going to use it for my project, cos I read so many good things about it, but am now unsure of whether to use it, cos if it was really that good, there would not have been 10 votes against.
Any advice would be appreciated.
Thanks.

I am researching into whether to use JDO for my
application.Good to see the sensei reseaching :)
I have read that polymorphism, inheritance and
complex relations are absent from EJB's. Is this
true? I am thinking that maybe the place where I have
read this are biased towards JDO, which is why they
have stated this, and would like to get a neutral
opinion.There are many threads on the forum as well as on http://theserverside.com on the same.
Also, I read at JDOCentral that The acceptance of
the Java Community Process� (JCP) JSR 243, also known
as JDO 2.0, is in jeopardy. The recent vote by the
JCP Executive Committee in the so called Public
Review Ballot resulted in 5 YES votes and 10 NO votes
and 1 abstention. I am a little confused. I keep
hearing that JDO is so good, if that is the case, why
was it rejected?Might have something to do with EJB 3.0
http://blog.hibernate.org/cgi-bin/blosxom.cgi/2004/05/07#ejb3
This blog discusses about the problem with JDO specs.
You see, I am going to use it for my project, cos I
read so many good things about it, but am now unsure
of whether to use it, cos if it was really that good,
there would not have been 10 votes against.This should really prevent you from using it! If JDo fits your design, you might still use it. But consider taking a look at Hibernate!
Cheers!
***Annie***

Im a complete beginner and i am stuck with ejb's...........................

Basically guys,
I have .ear file which i need to deploy on my local server somehow. I have java etc installed but I dont understand the deployment process.
I want to deploy the files and then load up the web application in a local browser. Basically the application contains a web portal which is what i will be dealing with mainly. I need to be able to run the jsp pages and see the outcome and make changes where required. Basically i want to create a development enviornment so that i can make changes and see the immediate effect.
Can someone help in this regard? THis is very urgent and any help will be much appreciated. Pls bare in mind im a newbie. Ive read lots of tutorials but im confused!

wat server do u have?

EJB Finder View Links and CMR

Hi,
Can someone please give me some input on the following warning in the JDeveloper online help!
"Warning: You cannot create an EJB finder view link that expresses the same relationship as a CMR."
I'm new to EJB, BC4J and JDeveloper. I created container managed entity beans with local interfaces only to represent my data and relationships. No problems with the mapping so far.
To test the beans I used Session Facades with remote interfaces and build a sample test client.
Now I thought I could create EJB Entity Facades, EJB Finder View Objects, EJB Finder View Links and EJB Application Modules to make use of the BC4J framework in order to speed up programming clients (JSP and JClient).
So I've started studying the JDeveloper online help (which seems to be very useful) and found the above mentioned warning.
Well, better a warning than nothing at all, but some more explanations would have been even better.
Is there no need to use view links with CMR?
How to achieve the same functionality (synchronizing two view objects in a master-detail-relationship) with CMR?
Do you know any examples? I couldn't find any examples using EJB entity facades in the "sample code" area on OTN.
Any comments about other (better) architectures are also welcome. Would it be better to use BMP entity beans in conjunction with BC4J?
Many thanks for your help!
Regards,
Eric

Steven,
thank you for your reply and suggestions - I'll count on that. If I find time I'll read this book. It seems to be very interesting.
For educational purposes I'd like to look at both persistence implementation strategies. I agree that it looks definitly easier to use entity objects. Certainly it's also performancewise a better choice.
Anyhow, could you give me some useful tips for cmp entity beans and finder view objects?
Is there something which works completely different if I use BC4J on top of it?
How to implement a master-detail relationship in JClient (Swing) for example?
What about writing an ejbfinder which doesn't return all, but all data where the foreign key is equal to a parameter passed to the finder method and use this as the source for a detail view object. This could be the primary key of the selected master. Well, I don't know whether this is doable. But that's what comes to my mind spontaneously.
Would this be a solution? I'm still thinking about the aforementioned warning in the online help regarding view links.
I guess the problem is that the foreign key is not part of the entity bean as it's not a cmp-field. Instead you have accessor methods to retrieve a related object or a collection of objects.
I'm sure my questions are not too complicated to answer. It's only hard for a beginner to get an overview.
I'm quite confident that I'll manage this if I give my best and get some help from knowledgeable people like you Steven.
Regards,
Eric

How much EJB I should to know?

Hi
Experts.
Hi i am making Guest house management system for a company in SAP netweaver and backend is oracle 10g.
i learned basics of sap webDynpro like
-->Navigation between views.
-->Context programming
-->Internationalization
-->Basic UI components like input field, table,.....
-->Dynamic programming.
Now to make this project efficient i have to know EJB to access database.
I don't know anything about EJB.
So how much EJB i need to know?
and what other things i need to know please provide good reference.
I am beginner in SAP webdynpro.
but I have good programming skills and learning skills.
Is there any good tutorials available for all this EJB and web dynoro connectivity?
and good tutorial with examples that teaches how to connect oracle and EJB?
and how to merge all this things?
Regards
Sunny Shah.

Hi
Check thesse links they maybe helpful to you
Webdynpro and Oracle
Oracle DB connectivity using EJB.
http://help.sap.com/saphelp_nw04/helpdata/en/b5/3f533e5ff4d064e10000000a114084/frameset.htm
oracle connection
http://help.sap.com/saphelp_nw04s/helpdata/en/86/f8fdceffa642d08cd198da565dbbbe/frameset.htm
http://help.sap.com/saphelp_nw04s/helpdata/en/d3/44d0ea14539a4f9b8ec204cedee9bf/frameset.htm
http://help.sap.com/saphelp_nw04/helpdata/en/e0/a00e408230c442e10000000a1550b0/frameset.htm
https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/0736159e-0301-0010-9ea4-c63d83d0797b
Regards
SURYA

EJB problem with home interface

Hi firends
I am beginner to EJB world, and trying first EJB object i.e. Hello World program
I prepared first Remote interface, HelloBean and it compiled also properly.
names of program
Remote interface : Hello
Bean: HelloBean
Home interface : HelloHome
But after preparing Home interface it fails to compile at position of create()
the declaration is
public Hello create() throws RemoteException,CreateException
compilation error pointing at Hello in above statement saying 'Cannot resolve symbol'
The fact is all these files are located in same directory only
can anyone help me in this problem as I am eger to execute my first program and want to go further in EJB
thanx in advance
Mandar

Hi Mandar,
How are you setting the classpath and what exactly is it set to?
Unresolved symbol can only mean that the class cannot be found in the classpath. If two files are in the same directory and one has a dependency on the other then adding '.' to the classpath is all that is needed. Questions to ask yourself. Are the files in the same directory? does either include a 'package' statement? and are you absolutely certain that the classpath is set correctly (type 'set' at the command line)? Also if you have set the CLASSPATH variable, using -classpath with the javac command will override the variable.
Check everything above and if you still have problems maybe we can get some more details if you can post the entire error message.
Mandy

Javax ejb CreateException: Could not create stateless EJB

Hi,
I have a JavaEE (EJB3.0) project deployed on glassfish2.1 as -.ear (exported from eclipse3.4 to the autodeploy-folder) with -.ejb.jar, -.webui.war, general-lib-base.jar (some other...)
The session bean is invoked by a jsf-managed bean. Have a pure annotation +@ejb+ in managed bean (identifiing the ejb-interface (+@Remote+) ...the ejb is annotated with +@stateless+
get the following error message:
*...nested exception is: javax.ejb.CreateException: Could not create stateless EJB*
as beginner in the JavaEE-field I'm looking for some help concerning the possible causes.
thank's for any comment...
(also posted in the Enterprise JavaBeans-forum possibly better there)

problem fixed: in the deployment-descriptor ejb-jar.xml a spezification of the session-bean hung around ...very annoying!

[beginner] Relationship between app server and JBI container

Hello,
I downloaded the Sun app server as well as the JBI SDK and I would like to understand how they relate to each other. Is the JBI SDK a plug-in in the app server? Does it run on top of it? What part of J2ee are used by JBI?(servlets, ejbs, JCA???).
Thanks in advance,
Julien.
PS
Any answer is welcome. I am a complete beginner in JBI and I am looking for some primer that will help me get started with the spec...

JBI is a specification; its up to the implementations to decide how they interact with different application servers. e.g. Sun's RI may work in Sun's app server and, say, JBoss. ServiceMix is already integrated into Apache Geronimo but has deployers for any Servlet engine and JBoss.
Typically a JBI container will use servlets for HTTP bindings and can use EJBs if required. JCA integration is an option too - e.g. ServiceMix can either integrate with the application servers JCA engine or can use its own embedded JCA engine - Jencks (http://jencks.org).
James
http://logicblaze.com/

Which of the following are true about abstract methods in EJB 2.0

Hi guys I'm beginner to EJB and i got some unanswered questions.
Can any one of you please.. give answers?
Thanks if you do...
Which of the following are true about abstract methods in EJB 2.0
CMP?
Choose all correct answers:
1. Abstract accessor methods should not be exposed in the EJB
component's interface
2.Abstract accessor/mutator methods are used to access and modify
persistent state and relationship information for entity objects
3.Abstract Accessor/Mutator methods do not throw exceptions
4.The EJB developer must implement the Accessor/Mutator methods
5.Abstract accessor methods may or may not be exposed in the EJB
component's interface
2.Which ONE of the following is true?
Choose the best answer:
1.Local interfaces cannot have a relationship with other Entity
components
2.Local interfaces cannot be used for Stateless Session EJB
3.Local interfaces can be a part of Object's persistent state
4.Local interfaces have the same functionality as that of a
stateless Session EJB
3.Which of the following describe the <cmr-field> in a EJB 2.0
descriptor?
Choose all correct answers:
1.A Local interface/Entity can be a value of a <cmr-field>
2.There is no <cmr-field> in EJB 2.0 descriptor
3.It is used to represent one meaningful association between any
pair of Entity EJBs, based on the business logic of the Application
4.It provides a particular mapping from an object model to a
relational database schema
5.It allows the Local Entity interfaces to participate in
relationships
4.Which of the following are the advantages of using Local interfaces
instead of dependent value classes?
Choose all correct answers:
1.Local Entity Interfaces can participate in Relationships
2.The life cycle of Local Entity Interfaces is managed by EJB
container, intelligently
3.Local Entity Interfaces can be used in EJB QL Queries
4.Local Entity Interfaces can be a part of the <cmp-field> but not
<cmr-field>
5.Which of the following are true about Local interfaces
1.A local interface must be located in the same JVM to which the EJB
component is deployed
2.Local calls involve pass-by-reference.
3.The objects that are passed as parameters in local interface
method calls must be serializable.
4.In general, the references that are passed across the local
interface cannot be used outside of the immediate call chain and must
never be stored as part of the state of another enterprise bean.
6.Which of the following specifies the correct way for a client
to access a Message driven Bean?
Choose the best answer:
1. via a Remote interface
2. via Home interface
3. Message driven bean can be accessed directly by the client
4. both 1 & 2
5. none of the above
------------------------------------------------------------------------7.Which of the following statements are true about message-driven
bean Clients?
------------------------------------------------------------------------Choose all correct answers:
They can create Queue and QueueConnectionFactory objects
They can create Topic and TopicConnectionFactory objects
They can lookup the JNDI server and obtain the references for
Queue and Topic and their connection Factories
Only 1 and 2 above

Hi guys I'm beginner to EJB and i got some unanswered
questions.
Can any one of you please.. give answers?
Thanks if you do...
Which of the following are true about abstract methods
in EJB 2.0
CMP?
Choose all correct answers:
1. Abstract accessor methods should not be exposed
d in the EJB
component's interfacefalse
2.Abstract accessor/mutator methods are used to
access and modify
persistent state and relationship information for
entity objectstrue
>
3.Abstract Accessor/Mutator methods do not throw
exceptionstrue
>
4.The EJB developer must implement the
Accessor/Mutator methodsfalse
5.Abstract accessor methods may or may not be exposed
in the EJB
component's interfacetrue
2.Which ONE of the following is true?
Choose the best answer:
1.Local interfaces cannot have a relationship with
other Entity
componentsfalse
2.Local interfaces cannot be used for Stateless
Session EJBfalse
3.Local interfaces can be a part of Object's
persistent statefalse
4.Local interfaces have the same functionality as
that of a
stateless Session EJBtrue
3.Which of the following describe the <cmr-field> in a
EJB 2.0
descriptor?
Choose all correct answers:
1.A Local interface/Entity can be a value of a
<cmr-field>true
2.There is no <cmr-field> in EJB 2.0 descriptorfalse
3.It is used to represent one meaningful association
between any
pair of Entity EJBs, based on the business logic of
the Applicationtrue
4.It provides a particular mapping from an object
model to a
relational database schematrue
5.It allows the Local Entity interfaces to
participate in
relationshipstrue
4.Which of the following are the advantages of using
Local interfaces
instead of dependent value classes?
Choose all correct answers:
1.Local Entity Interfaces can participate in
Relationshipsis
2.The life cycle of Local Entity Interfaces is
managed by EJB
container, intelligentlyis
3.Local Entity Interfaces can be used in EJB QL
Queriesnot
4.Local Entity Interfaces can be a part of the
<cmp-field> but not
<cmr-field>not
>
>
5.Which of the following are true about Local
interfaces
1.A local interface must be located in the same JVM
M to which the EJB
component is deployedtrue
2.Local calls involve pass-by-reference.true
3.The objects that are passed as parameters in local
l interface
method calls must be serializable.false
4.In general, the references that are passed across
s the local
interface cannot be used outside of the immediate
e call chain and must
never be stored as part of the state of another
r enterprise bean.true
>
6.Which of the following specifies the correct way for
a client
to access a Message driven Bean?
Choose the best answer:
1. via a Remote interfacefalse
2. via Home interfacefalse
3. Message driven bean can be accessed directly by
the clientfalse
4. both 1 & 2false
5. none of the abovetrue.
>
----------------7.Which of the following statements
are true about message-driven
bean Clients?
----------------Choose all correct answers:
They can create Queue and QueueConnectionFactory
objectsthe container can, dunno bout clients
>
They can create Topic and TopicConnectionFactory
objectsthe container can, dunno bout clients
>
They can lookup the JNDI server and obtain the
references for
Queue and Topic and their connection Factories
true
Only 1 and 2 abovefalse
somebody correct me if i'm wrong

EJB beginner

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