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EJB Overview
In this session, we are going to talk about basic and high level concept and
architecture of EJB. We still have 2 or possibly 3 more sessions for talking
about session beans, entity beans, message driven beans, security,
transaction, and persistence of EJB technology in detail later on.
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Agenda
? What is and Why EJB?
? EJB Architecture
? Component and Container Architecture
? Types of Beans
– Session beans, Entity beans, Message-Driven Beans
? Roles
? Anatomy of a EJB module
? How client invokes methods of EJB
? RMI communication model
? Deployment Descriptor & Packaging
So this is the agenda for this presentation. First, we will talk about what is EJB and then why
and when you want to use EJB for the development and deployment of enterprise applications.
Then we will spend some time talking about EJB architecture especially from the standpoint of
component and container architecture. This component and container architecture is a rehash
of what we already talked about in “J2EE overview”.
We will spend sometime talking about types of beans a bit. There are three types of beans
currently: session beans, entity beans, and message driven beans. Each of these bean type
addresses specific area of writing enterprise application.
In building and deploying EJB application, there is a clear separation of roles. For example,
the role that is played by bean developer is different from the role that is played by the
deployer. And we will talk about these logical roles.
We will look into the anatomy of EJB module. That is, when you build EJB module, as a bean
developer, the question of “what do you have to include in that module?” will be addressed
here.
We will talk about a bit on the RMI communication model between the client and EJB server.
Along with it, we will talk about the difference between local client view and remote client
view.
We will spend some time talking about deployment and packaging.
Finally we will talk about EJB security and transactions.
Again, we w