I want to know to work with EJB entity bean. I must deploy EJB entity bean in ejb container.
But I have seen some projects my friends working use java persistence api with EJB entity bean,
but they are deployed in servlet container instead of ejb container.
OpenEJB should be integrated with tomcat (Nowadays, there is tomcat EJB compatible version, it is called tomEE)
See How to deploy EJB based application on Tomcat
Related
I am working on migrating code base which has EJB 2.x as well as 3.x code.
How do I identify EJB 2.x code (session beans, message driven beans).
The code uses session beans with annotations and some beans are also defined in ejb-jar.xml.
I thought these annotated beans would be specific to 3.x code and the ones from ejb-jar.xml file would be 2.x beans , but then I found this class
#Stateless
#TransactionManagement(TransactionManagementType.BEAN)
public class ABC implements javax.ejb.SessionBean{
//methods
}
3.x beans do not implement javax.ejb.SessionBean right?
Is the above code snippet 2.x or 3.x ejb?
Let me know your thoughts
2.x EJB are required to implement SessionBean
3.x EJB are not required (but can) implement Session Bean
2.x EJB should have a Home interface
I have one webapplciation, i deployed it in server,server uses Jvm.
How jvm know the whether servelt object is created or not?
and one more thing In my web application having more than 5 servlet classes,then how jvm know which servlet instance created.
Servlets are declared in web.xml, when an application server which is in compliance with Servlet API start, it try to look for this file. In web.xml you have listed the servlet you want to load and the classes you should load in order to start servlets.
Servlets has their own lifecycle, if application server can not start a servlet, exception could be thrown then application server know that the servlet is no available.
Try to read more about servlets there many good tutorial over the net.
We have an old project written with EJB 2.1. Now we need to extend the project with the new requirements. But i don't want to use the old complicated EJB 2 again.
Is it possible to use EJB3.1/JPA in an existing project written with EJB 2.1.
P.S. Application Server is WebSphere
Yes, it is possible to reference EJB 3 from EJB 2. The older EJB applications can be deployed as is on EJB3.0 container since pre-EJB3.0 APIs are available in EJB3.0. Check these links out for detailed information:
http://www.coderanch.com/t/321218/EJB-JEE/java/EJB-call-EJB
https://community.jboss.org/wiki/ReferenceEJB3BeansFromEJB2Beans
A clean migration from EJB 2 to EJB 3 would be a better design choice though.
I'm learning about Java EE (EE 6 specifically) and find the differences between EJB and EJB Lite a little confusing.
Java EE6 web profile only supports EJB Lite.
My understanding of "EJB Lite" is that it is a simpler subset of EJB (I can find those differences documented easily enough) and you package your EJB classes in a WAR.
So will I only able to access those EJB classes from the webapp contained in the same WAR (or another webapp if I put both of them in the same EAR) ?
I assume that this means that the EJB Lite classes are deployed to the web container. Does this mean that there is no EJB container in the EE6 web profile ?
(also do we need a web-profile tag?)
Note that EJB lite is shared by both the web profile and the EJB embeddable container.
1.
So will I only able to access those
EJB classes from the webapp contained
in the same WAR (or another webapp if
I put both of them in the same EAR) ?
Section 20.4.3 of the EJB 3.1 spec:
The local client view(including the
no-interface view) of an enterprise
bean component defined within a .war
file is only required to be accessible
to components within the same .war
file. Applications needing access to
the local client view of an enterprise
bean from a different module in the
same application should use an ejb-jar
file to define the enterprise bean
that exposes the local client view.
Note, the spec allows vendor extensions so that other modules can use the EJBs, but relying on that won't be portable.
2.
assume that this means that the EJB
Lite classes are deployed to the web
container. Does this mean that there
is no EJB container in the EE6 web
profile ?
This is implementation specific, but given the existence of an embeddable EJB container, I suspect most implementations will ship either the full EJB container or a subset.
3.
(also do we need a web-profile tag?)
No.
Using JDeveloper as my IDE, I have a web application which calls services provided by annotated EJB 3.0 beans packaged in third party jar. How do I configure the web application project to deploy the beans to the embedded OC4J container when I run the application?
The jar file is referenced by the project, and I have a META-INF/application.xml referencing those jar files as EJB modules. I've set the EJB Version property to 3.0, but the Annotated EJB 3.0 Bean Classes list remains empty, presumably because I have no beans defined in the sources of the web application I'm running. When running the project, the embedded oc4j container warns that the EJB module contains no beans. I'd like to deploy the beans in the jar file, but can't figure out how.
JDeveloper 10.1.3.4
Windows Vista
The answer came from an OTN Discussion Forum:
Re: Deploying third party EJB 3.0 jar in web application
Posted: Nov 2, 2009 8:15 AM in response to: user10375549
Hi,
We've used ejb-jar.xml to register EJB3 session beans from third-party jars in JDeveloer 11g TP4 (which was using oc4j). The only difference was that beside third-party beans we had our own session beans (which didn't need to be registered in ejb-jar.xml).
Here is how we did it
<session>
<display-name>MySessionBean</display-name>
<ejb-name>MySessionBean</ejb-name>
<remote>some.package.MySessionBeanRemote</remote>
<ejb-class>some.package.MySessionBean</ejb-class>
<session-type>Stateless</session-type>
<transaction-type>Container</transaction-type>
</session>
I hope this helps you a bit.
Pedja