What is an enterprise java bean

Hi,
What is an enterprise java bean. How is it different from normal java means.
Thanks a lot,
Chamal.

Well an EJB is a object components that lives in the server's container's guts, there are 3 kinds of EJB:
* Session Beans: performs bussines operations
* Entity Beans: represents a table from a relational database
* Message Driven Beans: receives and controlls messages.
more information about it can be found at: http://java.sun.com/products/ejb/reference/docs/index.html

Similar Messages

Enterprise Java Beans

Hi,
I am a java programmer. I have worked with applets,
servlets, jdbc, etc., but I have never worked with EJB's
Is there a good tutorial of it? Does it depend on certain
API's? Where can I find the classes? I would like to learn
and to develop some applications with EJB's. I will appreciate a lot if someone give me the 1,2,3... of EJB's.
Thanks in advance

There are suspisiously many tutorials and materials on the Web about EJB.
The principals ones are at Sun's J2EE site:
http://java.sun.com/j2ee/tutorial/doc/J2eeTutorialTOC.html
PetStore Demo
http://java.sun.com/j2ee/download.html#blueprints
JGuru Exercises:
http://developer.java.sun.com/developer/onlineTraining/EJBIntro/exercises.html
Also, look at TheServerSide.com
http://theserverside.com/home/index.jsp
Tutorial on Monson-Haefer "Enterprise Java Bean" book:
http://www.techquestion.net/ejbs/cabinbean1.html
Be careful, however, sometimes it is difficult to repeate
what you have in tutorial.
Good luck,
Jacob Nikom

Using Enterprise Java Beans

Hi Guys,
Ive built a system which uses 8/9 servlets and connects to a postgres database, reads csv files and a few other things, now Ive been asked to implement this using java enterprise beans, how easy/difficult is this? how would I go about it and whats the advantages of using enterprise java beans?
Thanks
Tzaf

Can anyone help?
Thanks
Tzaf

The differents between Java Beans and Enterprise Java Beans

Please help me!
What is the differents between JavaBeans and Enterprise Java Beans (EJB) ?
Thank's for your answer

Enterprise Java Beans are special type of java beans.
EJBs invented to be used via remote VMs or remote computer
systems.They must be deployed on server to become accesible for remote
clients.

Adding new enterprise java beans in STUDIO CREATOR

I downloaded the 30 days trial version of Studio creator.
In my server navigator pane there is no Enterprise Java Beans node. How can I enable this node

Hi,
Can we consider this a duplicate thread of :
http://swforum.sun.com/jive/thread.jspa?threadID=53446&tstart=0
Thanks,
RK

Missing Enterprise Java Beans Node

I downloaded the Studio Creator 30 day trial version.
But In the server navigator pane there is no Enterprise Java Beans node listed.
How can I enable the Enterprise Java Beans Node in Studio Creator? Or is it a limited version?
Please reply asap.
Thanks in advance

Hi.
Porduct version information was as follows....
Java Studio Creator(Build 040903).
Does this mean that I need to upgrade my IDE to update 7?
Thanks a lot for the reply. I almost spent half a day trying to enable the Enterprise Java Beans Node using creator options.
And can I deploy an ear file to creator which I have compiled using JDK1.5?
Thanx again.
Look forward to hearsing from u soon,
Kevin

Accessing RFCs and BAPIs from enterprise java beans

Hello folks,
     my question is concerning comunication between EJBs and RFCs. I want to develop a simple session bean that connects to a R/3 back-end, calls a RFC then returns some data, let's say, an example of this could be a list of employees from BAPI_EMPLOYEE_GETDATA.
     Ok, by using a web dynpro and adaptive RFC my works could be very very easy, but I'd like to test this way: session (stateless) EJB -> RFC. Can I:
*     use JCO.ClientService with a non-portal SAP WAS?
*     use embedded JRA (SAP Library stated "The SAP JRA is an add-on for the SAP JCo. If you use      the SAP Web AS, the SAP JRA is installed automatically with the SAP JCo.", but I found      nothing so in Connector Container Service ...)
*     install and configure JRA by myself?
I'm working on a SAP WAS 6.40 Sneak Preview (Java only), and finding a path for easily integrate SAP WAS developed ejbs and external business system. SAP Library suggest to "obtain the JCo connection through the connection framework": is it related to JRA, JCA and SAP Resource Adapter?
Thank you
Pasquale

hello
i´ve written a simple stand alone client to test jra connection to a sap system
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.Properties;
import javax.resource.cci.Connection;
import javax.resource.cci.ConnectionFactory;
import javax.resource.cci.Interaction;
import javax.resource.cci.MappedRecord;
import javax.resource.cci.RecordFactory;
import javax.resource.cci.ResultSet;
import javax.resource.spi.ManagedConnectionFactory;
import com.sap.mw.jco.jra.*;
public class Example
     public void exampleTest()
          Properties properties = new Properties();
          Connection   connection=null;
          try
               properties.load(new FileInputStream ("props.txt"));
          catch(Exception e)
               System.out.println("properties could not be loaded");
               e.printStackTrace();
          try
               ManagedConnectionFactory mf = new JRA.ManagedConnectionFactoryImpl(properties);
               ConnectionFactory cf = (ConnectionFactory)mf.createConnectionFactory();
               connection = cf.getConnection();
               RecordFactory rf = cf.getRecordFactory();
               Interaction interaction = connection.createInteraction();
               MappedRecord request      = rf.createMappedRecord("STFC_STRUCTURE");
               // Since the STFC_STRUCTURE does not create any new records
               // in the data base, you do not need to start a trancation here.
               // fill out a structure with dummy data
               MappedRecord importstruct = (MappedRecord)request.get("IMPORTSTRUCT");
               importstruct.put("RFCFLOAT","1.23456");
               importstruct.put("RFCCHAR4","ABCD");
               importstruct.put("RFCINT1", "11");
               importstruct.put("RFCDATE", "2001-08-24");
               // fill out a table with dummi data
               ResultSet rfctable = (ResultSet)request.get("RFCTABLE");
               for (int i = 0; i < 10; i++)
                    rfctable.moveToInsertRow();
                    rfctable.updateString("RFCCHAR4","EFGH");
                    rfctable.updateInt("RFCINT1", i);
                    rfctable.updateString("RFCDATE", "1961-08-24");
                    rfctable.updateDouble("RFCFLOAT",1.65432);
                    rfctable.insertRow();
               // call defined RFC and cast the result to the optional ResultMap interface
               ResultMap response = (ResultMap)interaction.execute(null,request);
               // release resources
               interaction.close();
               // create an xml file from the output of the called RFC
               // the optional interface ResultMap offers additional methods, like writeXML
               FileOutputStream os = new FileOutputStream(response.getRecordName() + "_Structure_from_NotManaged_Example.xml");
               response.writeXML(new java.io.OutputStreamWriter(os,"UTF-8"),true);
               os.close();
               ResultSet resultSet = (ResultSet)response.get("RFCTABLE");
               System.out.println("Name of the table is: "+resultSet.getRecordName());
          catch (Exception ex)
               ex.printStackTrace();
               System.exit(1);
          finally
               if (connection != null)
                    try
                         connection.close();
                    catch(Exception exception1)
     public static void main(String[] args)
          Example anExample = new Example();
          try
               anExample.exampleTest();
          catch(Throwable t)
               t.printStackTrace();
the property file looks like this:
jco.client.client=010
jco.client.user=user
jco.client.passwd=pass
jco.client.ashost=your host
jco.client.sysnr=00
but this only an example for a standalone test client
to use jra inside j2ee first deploy the connector with the settings you need and then get a connection to it using jndi
i don´t have an example at hand for using it inside an ejb or servlet, but if you need one i'll have a look

Enterprise Java Beans how to start??

Hi All,
I am new to EJB. I need to use EJB in my finantial Application.
Can anybody tell me how to start learning EJB??
We are using WebSphere Application Server..There are lots of material availabe ..but its enough to make me confuse..
I dont know what to do and from where to start.It will be good if anybody can guide me.i want conceptual understanding not just implementation guidence.
thanks in advance.

I think a good start is
http://java.sun.com/javaee/5/docs/tutorial/doc/index.html
It will give help you to understand...
If you dont preffer to study thousands sites of material... (Im wondering why :-) ), you can start by:
http://wiki.jboss.org/wiki/Wiki.jsp?page=StarterSkeletonEclipseProject
http://www.onjava.com/pub/a/onjava/2006/05/17/standardizing-with-ejb3-java-persistence-api.html
http://www.javaworld.com/javaworld/jw-08-2004/jw-0809-ejb.html
and the very good collection of materials is also available here:
http://www.javaworld.com/channel_content/jw-ejbs-index.shtml?
quick overview:
http://www.solarmetric.com/resources/ejb-api-quickref.pdf
timony

SIngle Sign On and Enterprise Java Beans

We are using mod_osso to sign on to a JSP application.
The JSP application then needs to invoke methods on EJBs residing in a different OC4J.
How does the JSP application bind to the EJB such that the security credentials of the user who logged in are inherited by the EJB.
Cheers,
Andy.

The best approach is to implement the Java applications as SSO partner applications so that they delegate their authentication to the Login Server, thereby leveraging the same credentials as used to login to the Portal.
The SSO-SDK which is required to implement a partner application is available from technet:
Portal Development Kit
SSO Software Development Kit
Example Java Application Written as an SSO Partner App
null

Accessing XMLType and CLOB from Enterprise Java Beans

When trying to create a temporary CLOB within the application server the following exception
occurs (connection from Jndi):
Oracle9iAS (9.0.2.0.0) Containers for J2EE initialized
AccessEJBBean.meld: ex=java.lang.NullPointerException java.lang.NullPointerException
at oracle.sql.LobPlsqlUtil.plsql_createTemporaryLob(LobPlsqlUtil.java:1352)
at oracle.jdbc.dbaccess.DBAccess.createTemporaryLob(DBAccess.java:997)
at oracle.sql.LobDBAccessImpl.createTemporaryClob(LobDBAccessImpl.java:240)
at oracle.sql.CLOB.createTemporary(CLOB.java:527)
at com.access.impl.AccessEJBBean.meld(AccessEJBBean.java:67)
(email: [email protected] )

When trying to create a temporary CLOB within the application server the following exception
occurs (connection from Jndi):
Oracle9iAS (9.0.2.0.0) Containers for J2EE initialized
AccessEJBBean.meld: ex=java.lang.NullPointerException java.lang.NullPointerException
at oracle.sql.LobPlsqlUtil.plsql_createTemporaryLob(LobPlsqlUtil.java:1352)
at oracle.jdbc.dbaccess.DBAccess.createTemporaryLob(DBAccess.java:997)
at oracle.sql.LobDBAccessImpl.createTemporaryClob(LobDBAccessImpl.java:240)
at oracle.sql.CLOB.createTemporary(CLOB.java:527)
at com.access.impl.AccessEJBBean.meld(AccessEJBBean.java:67)
(email: [email protected] )

Can Enterprise Java Beans interact with any database system

Hello:
I was wondering if someone can tell me if the Enterprise javabeans can work with any database (like multi-valued database for example Universe)?
Thanks in advance.
Rino

Yes

Separation of WebService & Enterprise Java Beans on two different Machines

All,
Have anybody been able to separate the webservices and the ejb's into two weblogic
servers. To be precise, I want to invoke a web service and the web service should
be able to talk to the weblogic server a different one than that is hosting the
webservice to execute the ejb methods.
Any help would be appreciated.
Thanks,
--Pratap

Rob, thanks for your input. theoretically,
i agree with you. but using a pure web server
to pick up web services request nicely fits
the already widely accepted web-tier/ejb-tier
design and implementation.
could you please take a look at my message
184 Help needed in web service example - "david zhang" , 10 Dec 2001
i really need some help on that. thanks in advance.
david
Rob Woollen <[email protected]> wrote:
There's pros and cons to both approaches.
The reasons that I generally recommend co-location are:
1) Much better performance -- We can optimize the web/web service -->
EJB call to be a direct method call. If they are in separate
processes/machines, you will need to go through rmi marshalling and
unmarshalling of the data and send your requests over a network connection.
2) one less remote programming error case to handle -- Anytime that you
make a remote call, you need to handle a set of error cases that do not
occur with in-process calls. Failures during marshalling, sending the
request, during the response etc. Distributed programming is hard.
I would avoid it whenever possible.
-- Rob
david zhang wrote:
maybe i have the same thoughts as Pratap has.
i notice that this is actually a difference
between Apache SOAP implmentation and Weblogic
web service implementation. In the Apache's
implementation, a pure WEB server with a servlet
engine is able to pick up a service request.
if the request handler needs to use an EJB running on
another application server, it just call it.
so with apache implementation, i can put all EJBs
on one application server. with weblogic's implementation,
there has to be an APPLICATION server up front to
to pick up a web service. sounds like an overkill or
in elegant design. actually, Sun blueprints has an article
"Initial Thoughts on Web Services", and it is my understanding
that a web tier should pick up a web service.
Rob, please give us the magic:-)
regards,
david
Rob Woollen <[email protected]> wrote:
It's possible to do this, but I wouldn't recommend the configuration.
Why do you
want to do this?
-- Rob
Pratap Srivastav wrote:
All,
Have anybody been able to separate the webservices and the ejb's
into
two weblogic
servers. To be precise, I want to invoke a web service and the
web
service should
be able to talk to the weblogic server a different one than that
is
hosting the
webservice to execute the ejb methods.
Any help would be appreciated.
Thanks,
--Pratap

What is java beans?

what is the difference between java application and java beans?
thanks!

Hmm, I'm gonna have a go at this - hopefully someone will build on it with more differences or requirements:
A Java Bean is merely a Java class written to conform to some simply rules for construction and method naming eg:
public class MyBean
private String myField;
public MyBean()
public void setMyField(String myField)
this.myField = myField;
public String getMyField()
return myField;
}Applications can use Java Beans without having to know about the class in advance - a typical situation might be their use in visual GUI editors where the properties of the bean can be exposed and manipulated by the editor through examination of the method names or an accompanying descriptor.
An Enterprise Java Bean doesn't have all that much in common with a Java Bean. An EJB is a small set of classes meeting a single (usually) business requirement written to conform to the EJB specification. This enables them to be used by J2EE Application servers to perform enterprise business functions (data storage, manipulation, business logic etc.). The whole idea is that by writing to the specification the server can automatically provide support for transaction management, concurrent access, scaleability, etc that a mission-critical system might require without the programmer having to understand the workings of the application server.
Essentially an EJB can either
1) maintain the permanent state of a business object (eg, hold the data for a single product in a catalogue)
2) perform a small set of business operations (eg, place an order for a customer)
3) act in response to messages passed around the system (eg, send a mail to the user when the items have been shipped)
I would have a look at the following two pages to get a better overview:
http://java.sun.com/products/javabeans/
http://java.sun.com/products/ejb/
Hope this helps.

What is the difference between Java Beans and EJBs ?

Hi,
Can someone tell me that ? Kind of confused... Thanks !
Philip

Hmm, I'm gonna have a go at this - hopefully someone will build on it with more differences or requirements:
A Java Bean is merely a Java class written to conform to some simply rules for construction and method naming eg:
public class MyBean
private String myField;
public MyBean()
public void setMyField(String myField)
this.myField = myField;
public String getMyField()
return myField;
}Applications can use Java Beans without having to know about the class in advance - a typical situation might be their use in visual GUI editors where the properties of the bean can be exposed and manipulated by the editor through examination of the method names or an accompanying descriptor.
An Enterprise Java Bean doesn't have all that much in common with a Java Bean. An EJB is a small set of classes meeting a single (usually) business requirement written to conform to the EJB specification. This enables them to be used by J2EE Application servers to perform enterprise business functions (data storage, manipulation, business logic etc.). The whole idea is that by writing to the specification the server can automatically provide support for transaction management, concurrent access, scaleability, etc that a mission-critical system might require without the programmer having to understand the workings of the application server.
Essentially an EJB can either
1) maintain the permanent state of a business object (eg, hold the data for a single product in a catalogue)
2) perform a small set of business operations (eg, place an order for a customer)
3) act in response to messages passed around the system (eg, send a mail to the user when the items have been shipped)
I would have a look at the following two pages to get a better overview:
http://java.sun.com/products/javabeans/
http://java.sun.com/products/ejb/
Hope this helps.

Java Bean v/s EJB

Hi All,
Could anyone explain to me what is the difference between a normal Java Bean and an enterprise java bean (EJB). And when would one go for Java Beans and When for an EJB ??
I am a newbie in J2EE. Please Help...
Thanks in advance,
Arun

Its ok man.Refer to the documentaion on the same site. You wil get the ansewrs.
-Kshitij.

What is an enterprise java bean

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