Why do we use a home interface in EJB

I am trying to figure out why we need to use a HOME Interface in every EJB that we deploy in a container ? What is the significance ?
Thanks

Some info:
A home interface defines the methods that allow a client to create, find, or remove an enterprise bean. The home interface is EJB's way of creating an object. Home interfaces act as factories to create session beans and entity beans. The home interface defines the bean's life cycle methods, One of two interfaces for an enterprise bean. The home interface defines zero or more methods for creating and removing an enterprise bean. For session beans, the home interface defines create and remove methods, while for entity beans, the home interface defines create, finder, and remove methods.
You may want to also look up:
http://java.sun.com/j2ee/learning/tutorial/
http://java.sun.com/developer/onlineTraining/J2EE/Intro2/j2ee.html

Similar Messages

Why do we need a Home Interface?

Hi Guys,
I am new to EJB. i am some questions.
1) Why do we need a Homeinterface?
2) Where does container generated classes for both the interface located(assume we have 2 machine, one is client and another is server)
In RMI we hv stubs and skeletons located in client and server side....similarly how it is designed in EJB?
Thanks & Regards
-vijay

In EJB3.0 the home interface has been removed. The purpose of home interface was to serve as a factory for finding/creating/destroying an enterprise bean instance. I am not sure why exactly the architects of ejb created a home interface. May be they thought its better to have a clear seperation of responsibilities, that is home interface for the above said purpose and component interface (a.k.a remote interface) for executing the business methods. Also you need to understand that the client never deals directly with a bean instance. The client always calls a bean's home or remote interface methods whose execution is delegated to the actual bean instance. This mechanism provided more flexibility for the container in creating and managing enterprise bean's instances. Hope this helps.

Why do I use local bean interfaces?

When can I use a local bean interface?
Is it when the beans are deployed in the same manufacturers container system or do the beans just have to reside on the same physical machine?

Yes, you should always write local interfaces when
both web and ejb container using the same JVM.
This is incorrect. The EJB Local view (as opposed to the EJB Remote view)
can only be accessed by :
1) an EJB within the same ejb-jar
2) an EJB within a different ejb-jar but packaged within the same .ear
3) a web component(servlet or jsp) in a .war packaged within the same .ear
An ejb or web component in a different application(.ear) cannot portably
access the Local EJB view.
Kenneth Saks
J2EE SDK Team
SUN Microsystems
You can search out about more on local interface for
solving data-aliasing problem.

What is the use of Remote and Home Interface in EJB's?

Is it like a stub and skeleton or any other purpose

Home interface is handling the lifecycle events while Remote is handling the logic or other Business methods

Remote and Home Interfaces

Why do we need a home interface and remote interface for a ejb.
Must these interfaces be there for each ejb?

Why do we need a home interface and remote interface
for a ejb.The Home interface is like a factory for getting to your beans. The remote interface is what you use to speak "directly" to the bean. It's remote because the bean is usually on a remote server somewhere (not in the same VM as your client code). The same is true for the home interface in terms of it being remote.
The corresponding LocalHome and Local interfaces are for use when the bean in question is not remote.
Must these interfaces be there for each ejb?You need either a Home and Remote or LocalHome and Local interface for all beans except Message Driven Beans.

How to find out local or home interface was used ?

Hi !
are there any ways in the code of methods ejbCreate and ejbRemove in my entity EJB to find out were they called via local or home interface provided that my bean has both local or home interfaces ?
Thenks in advance.

Why should you care, this logic should only be implemented in the client (SEJB or Servlet). Even then it should only be used to check if there is a LocalHomeInterface. If not you get the RemoteHomeInterface. I don't understand the question completely.

I have ipad2, using wifi home network and ios7. Why I cannot play youtube...help!

I have ipad2, using wifi home network and ios7. Why I cannot play youtube...help!

You don't download anything at all. The feature is built into the iPhone 4 already. Your carrier has to support the feature and there might be an extra charge to use it.
You can read about how it works here.
iOS: Understanding Personal Hotspot - Support - Apple

What is the significance of Marker interface? Why are we using, even though

What is the significance of Marker interface? Why are we using, even though it has no method?

Well, what's the significance of an interface? They can define a set of methods a class may implement but the class could equally well implement these methods without the interface so why having interfaces at all?
The answer is that the most important aspect of an interface is that it constitutes a type (you can declare variables of it). And it's a type regardless of how many methods it defines, including none. So the reason for having a marker interface is that you're interested solely in the type aspect of interfaces.

TS3899 When at home using our home wireless I can send and receive emails on my iPad no problem. When using other wireless networks I can send emails to people who share the same Internet provider but not others. Why?

Is the wireless provider the issue? I can receive emails everywhere I go but in some locations can only send to a limited number of email addresses.

Greetings
I suspect that the issue is the SMTP server settings. On your home network you are using your providers SMTP server and all is fine (If you check your email account configs you will find that the SMTP server is set to your providers?).
When you use a different network (provider) mail will not be sent unless you use that networks (providers) SMTP server (this is a security issue to address ways of "spamming").
So if youre 3G/4G provider is the same as you home provider all will work well via your home WiFi. If you turn off WiFi and just use your 3G/4G connection to send mail (iPhone/iPad etc) all will work well (when you are out and about and using anothers WiFi network).
If you are connected to, say a MacDonalds WiFi, mail will probably not be sent. (It will be received though).
Using WEB mail interface (via your WEB browser) removes this problem as well.
(A SMTP server is what is used to send email. So to successfully use anothers (not a networks the same as your providers) WiFi network and send email via it, you must know the SMTP servers name and reconfigure your email account/s to use that server to send mail.)

Unable to bind EJB Home Interface to the JNDI name

Why do I get this error?? What is the jndi-name in weblogic-ejb-jar.xml
Unable to deploy EJB: OrganizationEJB from sempire_bc.jar:
Unable to bind EJB Home Interface to the JNDI name:
com.sempire.builder.business
_component.Organization. The error was:
javax.naming.NameAlreadyBoundException: Organization is already bound;
remaining
name 'com.sempire.builder.business_component'
<<no stack trace available>>

Slava,
In case I change the name of the jndi name to a unique name. I still get the same
problem. I checked for multiple occurences, but there aren't any.
My web.xml file is:
<ejb-local-ref>
<description>
Reference EJB resources in Weblogic Resources
</description>
<ejb-ref-name>GangsterEJB</ejb-ref-name>
<ejb-ref-type>Entity</ejb-ref-type>
<local-home>com.sempire.builder.business_component.GangsterHome</local-home>
<local>com.sempire.builder.business_component.Gangster</local>
</ejb-local-ref>
My weblogic-ejb-jar.xml file is:
<weblogic-enterprise-bean>
<ejb-name>GangsterEJB</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>
<resource-description>
<res-ref-name>jdbc/GangsterDB</res-ref-name>
<jndi-name>oraclePool</jndi-name>
</resource-description>
</reference-descriptor>
<local-jndi-name>Gangster_test</local-jndi-name>
</weblogic-enterprise-bean>
I do not get the problem.
Thank you
Ronak Parekh
"Slava Imeshev" <[email protected]> wrote:
Hi Ronak,
This exception means that you already have a bean
with the same JNDI name. Search your weblogic-ejb-jar.xml files
for multiple occurrences of the name and fix the problem.
Regards,
Slava Imeshev
"Ronak Parekh" <[email protected]> wrote in message
news:[email protected]...
Why do I get this error?? What is the jndi-name in weblogic-ejb-jar.xml
Unable to deploy EJB: OrganizationEJB from sempire_bc.jar:
Unable to bind EJB Home Interface to the JNDI name:
com.sempire.builder.business
_component.Organization. The error was:
javax.naming.NameAlreadyBoundException: Organization is already bound;
remaining
name 'com.sempire.builder.business_component'
<<no stack trace available>>

JSP Home Interface Problems

Hi, I am havin some problems trying to create a home interface in a JSP from an enterprise bean, i am using the following code :
<%!
     private AddressBook addressbook = null;
     public void jspInit()
          try
               InitialContext ic = new InitialContext();
               Object objRef = ic.lookup("java:comp/env/ejb/TheAddressBook");
               AddressBookHome home = (AddressBookHome)PortableRemoteObject.narrow(objRef, AddressBookHome.class);
               %> <%!
               addressbook = home.create("a","a","a","a","a","a","a");
          catch (RemoteException ex)
            System.out.println("Couldn't create AddressBook bean."+ ex.getMessage());
        catch (CreateException ex)
            System.out.println("Couldn't create AddressBook bean."+ ex.getMessage());
        catch (NamingException ex)
            System.out.println("Unable to lookup home: "+ "AddressBook "+ ex.getMessage());
     public void jspDestroy()
     addressbook = null;
%>
     <%
     addressbook01 = home.create("b","a","a","a","a","a","a");
     %>However i cannot access the home interface in the body of the JSP, i.e. where addressbook01 is trying to be created. Does anyone know a way around creating the home interface so that it is accessible in the body of the JSP?
cheers

Milan,
I will attempt to answer some of your questions. Others I need a little more detail on:
1. There isn't a way to run a JSP directly from JDeveloper to TomCat. Our internal server, Web-to-Go, is what we provide for local testing and debugging.
We do, however, support remote debugging JSPs against TomCat. You can find out more about how to set this up from the online help, and also from the JDev 3.1 Remote Debugging Online Demo Walkthroughs available on the JDeveloper OTN page.
2. I'm not sure why this is happening, but I would just answer 'No', if your edits are getting wiped out. I have not experienced this problem myself when I select 'Yes'.
3. Are these JSP files that JDeveloper has created (i.e. via the JSP Web Application Wizard), or ones you created yourself? Does this happen each time you open the project? What are your HTML source and root directories set to in your Project Properties? Are the JSP files located there?

The display on my iPod is extra large and I am have no idea why. I tried the HOME button and the power button at the same time but that doesn't work. I can't even enter my code to unlock it because I cannot scroll the HUGE display! Any ideas??

The display on my iPod Touch is HUGE and I have no idea why. I tried the HOME button and power button at the same time.....no help. I cannot enter my unlock code because I can't scroll without entering a wrong number! HELP!!

Using three fingers, double-tap the screen.
http://support.apple.com/kb/TS3129

Use of abstract interface

I have a series of questions....... Go through.
What is the use of abstract interface in java ?
What is the use of static object in java ?
What is the use of abstract key word to variables ?
Object reference passed to method are final. Can ' t we change it ?

class Testing {
     int i;
public class RefFinal {
   public static void f ( Testing t1, Testing t2) {
       Testing temp;
       temp=t1;
       t1=t2;
       t2=temp;
       System.out.println("value of i in t1 =" +t1.i);
       System.out.println("value of i in t2 =" +t2.i);
   public static void main( String args[]) {
      Testing t1 = new Testing();
      Testing t2 = new Testing();
      t1.i=10;
      t2.i=20;
      f(t1,t2);
      System.out.println("value of i in t1 =" +t1.i);
      System.out.println("value of i in t2 =" +t2.i);
}      Here the code explain why?

Using one Message Interface for all mappings

Hi Folks,
I am using a BPM in which i m getting a file from file system which have system ID in it.
I am having three send Synchronous step following that.
What i need is to use the Message interface for file to be used for receiver determination based on system id in case of Synchronous interfaces.
DO i need to include this File msg. interface in each mapping, if i do so will it be possible to send req. and get response for synchronous call.
OR is there any way to to use the file msg. interface for each mapping.
we are on SP17,I also tried Extended mapping but i am having SYNCHRONOUS send steps.
Plz help me out
Sachin

Bhavesh
<i>1. You receiver a file in your BPM . This has a field called SYSTEM ID?
2. On the basis of the System ID field you need to determine the Receiver to which the Synchronous Request message has to be sent?</i>
Sorry for that...because I was confused with jai's ans.. that's why said like that
<b>You are absolutely correct</b>
This is what i want to do.
i can't use switch step here. my BPM looks like this
RecFile->sync send->transformation1->transformation2->sync send2->transformation3->BLOCK
in BLOCK
Sync Send3->transformation4 and so on...
I am using three different Sync ABS Interface for each Sync send steps.
In receiver determination i want to get the data from respective R/3 system based on system ID i.e. logical system in File MI.
Say if it T90CLNT90 then get data from BS_SAPR3_4.6 else from BS_4.7
Sachin
Message was edited by:
Sachin Dhingra

Unable to deploy EJB 3.0 on JBoss 4.0.4GA - no home interface

I am stuck in that my EJB3.0 project (one entity bean, one session bean and one client test bean) builds OK but somehow Eclipse Europa is unable to deploy it to JBoss (4.0.4 GA and 5 Beta) -- something to do with JNDI error as it involves javax.naming exceptions.
My Eclipse directory structure is :-
Titan (project name)
|
ejb - com.titan (package name)
| |
| domain -> Cabin.java (my entity bean)
| |
| travelagent -> TravelAgentBean.java
| -> TravelAgentRemote.java
|
META_INF -> ejb-jar.xml
-> MANIFEST.MF
-> persistence.xml
My ejb-jar.xml is :
<?xml version="1.0" encoding="UTF-8"?>
<ejb-jar id="ejb-jar_ID" version="2.1" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/ejb-jar_2_1.xsd">
<display-name>Titan</display-name>
<enterprise-beans>

<session >
<display-name>TravelAgentBean</display-name>
<ejb-name>com/titan/travelagent/ejb/TravelAgentBean</ejb-name>
<remote>com.titan.travelagent.ejb.TravelAgentRemote</remote>
<ejb-class>com.titan.travelagent.ejb.TravelAgentBean</ejb-class>
<session-type>Stateless</session-type>
<transaction-type>Container</transaction-type>
</session>
</enterprise-beans>
</ejb-jar>
And my persistence.xml is :
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
<persistence-unit name="Titan">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<class>com.titan.domain.Cabin</class>
<properties>
<property name="hibernate.connection.driver_class" value="oracle.jdbc.OracleDriver" />
<property name="hibernate.connection.url"
value="jdbc:oracle:thin:@localhost:1521:XE" />
<property name="hibernate.connection.username" value="SYSTEM" />
<property name="hibernate.connection.password" value="Swordfish1" />
</properties>
</persistence-unit>
</persistence>
I right-click on the Titan project name and choose Build Project. I get the following error message :-
13:01:06,046 WARN [verifier] EJB spec violation:
Bean : com/titan/travelagent/TravelAgentBean
Section: 7.11.2
Warning: A Session bean must implement, directly or indirectly, the javax.ejb.SessionBean interface.
13:01:06,046 WARN [verifier] EJB spec violation:
Bean : com/titan/travelagent/TravelAgentBean
Section: 7.11.3
Warning: A Session bean must define at least one ejbCreate method.
13:01:06,046 WARN [verifier] EJB spec violation:
Bean : com/titan/travelagent/TravelAgentBean
Section: 7.11.1
Warning: The session bean must implement either a remote home and remote, or a local home and a local interface or a service endpoint interface.
13:01:06,062 ERROR [MainDeployer] Could not create deployment: file:/C:/jboss-4.0.4.GA/server/default/deploy/Titan.jar
I don't understand, because as of EJB 3.0, you don't really need a home or local-home interface anymore...

Using @SecurityDomain("exemplo1") in my EJB and NOT providing jboss.xml, it works.
@SecurityDomain("exemplo1")
@RolesAllowed("yyy")
@Stateless(name="UserManagement")
public class UserManagementBean implements UserManagement {
public void add(User user) {
}Damn! This is some serious shit... I don�t want to configure this in every single EJB.
EJB 3.0 is nice, but some small trivial details like this and others, that was forgotten by Sun, piss me off!

Why do we use a home interface in EJB

Similar Messages

Maybe you are looking for