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Java 2 Platform Enterprise Edition(J2EE)
A Model for Enterprise Application Development
Report from the Java Days Conference
Athens,Greece 17/01/2002
Nikolaos Th. Korfiatis
([email protected])
Research Assistant
Information Systems Technologies Laboratory
Department of Management Science and Technology
Athens University of Economics and Business
Athens, Greece
Nikolaos Korfiatis
Dept. of Management & Technology-Athens University of Economics and Business
The Java 2 Enterprise Edition Platform
The Platform for Enterprise Solutions
According to SUN the J2EE platform :

Represents a single standard for implementing and deploying
enterprise applications.

Has been designed through an open process.

Is engaging a range of enterprise computing vendors, to
ensure that it meets the widest possible range of enterprise
application requirements.

Addresses the core issues that impede organizations’ efforts to
maintain a competitive place in the information economy.
Nikolaos Korfiatis
Dept. of Management & Technology-Athens University of Economics and Business
The Java 2 Enterprise Edition Platform
J2EE Architecture Overview
The J2EE architecture is designed to provide server-side
and client-side support for :
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Developing enterprise, multitier applications.
Providing client services and business logic for an
application, and backend enterprise information
systems
Providing data and knowledge management.
Nikolaos Korfiatis
Dept. of Management & Technology-Athens University of Economics and Business
The Java 2 Enterprise Edition Platform
J2EE Platform Benefits
With a set of features designed specifically to expedite the
process of distributed application development, the J2EE
platform offers several benefits such as:
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Simplified architecture and development
Scalability to meet demand variations
Integration with existing information systems
Choices of servers, tools, components
Flexible security model
Nikolaos Korfiatis
Dept. of Management & Technology-Athens University of Economics and Business
The Java 2 Enterprise Edition Platform
Simplified Architecture and Development

The J2EE platform supports a simplified, component-based
development model.

Because it’s based on the Java programming language and the
Java 2 Platform, Standard Edition (J2SE TM platform), this
model offers Write Once, Run Anywhere portability, supported by
any server product that conforms to the J2EE standard.

The component-based J2EE development model can enhance
application development productivity in a number of ways
Nikolaos Korfiatis
Dept. of Management & Technology-Athens University of Economics and Business
The Java 2 Enterprise Edition Platform
Simplified Architecture and Development

Maps easily to application functionality:

Component-based application models map easily
and flexibly to the functionality desired from an
application.

Component-based design also simplifies application
maintenance, since components can be updated and
replaced independently new functionality can be
shimmed into existing applications simply by
updating selected components.
Nikolaos Korfiatis
Dept. of Management & Technology-Athens University of Economics and Business
The Java 2 Enterprise Edition Platform
Simplified Architecture and Development (2)
 Enables assembly- and deploy-time behaviors:

Components can expect the availability of standard
services in the runtime environment, and can be
dynamically connected to other components
providing well-defined interfaces.

As a result, many application behaviors can be
configured at the time of application assembly or
deployment, without any recoding required.
Nikolaos Korfiatis
Dept. of Management & Technology-Athens University of Economics and Business
The Java 2 Enterprise Edition Platform
Simplified Architecture and Development (3)

Supports division of labor

Components help divide the labor of application
development among specific skill sets, enabling
each member of a development team to focus on
his or her ability.

Thus, JSP templates can be created by graphic
designers, their behavior by Java programming
language coders, business logic by domain experts,
and application assembly and deployment by the
appropriate team members.

This division of labor also helps expedite application
maintenance.
Nikolaos Korfiatis
Dept. of Management & Technology-Athens University of Economics and Business
The Java 2 Enterprise Edition Platform
Integrating Existing Enterprise Information Systems
The J2EE platform, together with the J2SE platform, includes a
number of industry standard APIs for access to existing enterprise
information systems. Basic access to these systems is provided by
the following APIs:
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JDBC TM is the API for accessing relational data from Java.
The Java Naming and Directory Interface TM (JNDI) is the API
for accessing information in enterprise name and directory
services.
The Java Message Service (JMS) is the API for sending and
receiving messages via enterprise messaging systems like IBM
MQ Series and TIBCO Rendezvous.

JavaMail TM is the API for sending and receiving email.
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Java IDL is the API for calling CORBA services.
Nikolaos Korfiatis
Dept. of Management & Technology-Athens University of Economics and Business
The Java 2 Enterprise Edition Platform
Support for Business Logic Components
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In the J2EE platform, middle-tier business logic is implemented in
the middle tier as Enterprise JavaBeans components (also referred
to as enterprise beans). Enterprise beans allow the component or
application developer to concentrate on the business logic while
the complexities of delivering a reliable, scalable service are
handled by the EJB server.
The J2EE platform and EJB architecture have complementary
goals. The EJB component model is the backbone of the J2EE
programming model. The J2EE plat-form complements the EJB
specification by:
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Fully specifying the APIs that an enterprise bean developer can
use to implement enterprise beans.
Defining the larger, distributed programming environment in
which enterprise beans are used as business logic
components.
Nikolaos Korfiatis
Dept. of Management & Technology-Athens University of Economics and Business
The Java 2 Enterprise Edition Platform
Scalability

J2EE containers provide a mechanism that supports simplified
scaling of distributed applications, without requiring any effort on
the part of the application development team. Because J2EE
containers provide components with transaction support, database
connections, life cycle management, and other features that
influence performance, they can be designed to provide scalability
in these areas. This can achieved, by :
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Providing database connection pooling so containers can
ensure that clients will have access to data quickly.

By allowing server providers freedom to configure containers
to
run
on
multiple
systems.
Web
containers
can
be
implemented to perform automatic load balancing as the
demand for a particular application fluctuates.
Nikolaos Korfiatis
Dept. of Management & Technology-Athens University of Economics and Business
The Java 2 Enterprise Edition Platform
Choice of Servers, Tools, and Components
The J2EE standard and J2EE brand are central to creating a
marketplace for servers, tools, and components. The J2EE brand
on a server product ensures the kind of ubiquity that’s
fundamental to the goals of the J2EE platform. In addition, J2EE
standards ensure a lively marketplace for tools and components.
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A range of server choices:
Application development organizations can expect J2EE
branded platforms from a variety of vendors, providing a range
of choices in hardware platforms, operating systems, and
server configurations. This ensures that businesses get a
choice of servers appropriate to the strategic purpose of the
applications they need.
Designed for tool support
Both EJB and JSP components are designed to be manipulated
by graphical development tools, and to allow automating many
of the application development tasks traditionally requiring the
ability to write and debug code.
Nikolaos Korfiatis
Dept. of Management & Technology-Athens University of Economics and Business
The Java 2 Enterprise Edition Platform
Choice of Servers, Tools, and Components
Both J2EE server providers and third-party tool developers can
develop tools that conform to J2EE standards and support
various application development tasks and styles. Application
developers get a choice of tools to manipulate and assemble
components, and individual team members may choose tools
that suit their specific requirements best.

A marketplace for components
Component-based design ensures that many types of behavior
can be standardized, packaged, and reused by any J2EE
application. Component vendors will provide a variety of offthe-shelf component solutions, including accounting beans,
user interface templates, and even vertical market
functionality of interest in specific industries. Application
architects get a choice of standardized components to handle
common or specialized tasks.
Nikolaos Korfiatis
Dept. of Management & Technology-Athens University of Economics and Business
The Java 2 Enterprise Edition Platform
Simplified, Unified Security Model
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The J2EE security model is designed to support single signon access to application services. Component developers
can specify the security requirements of a component at
the method level, to ensure that only users with
appropriate permissions can access specific data
operations.
While the EJB and Java Servlet APIs both provide
mechanisms for building security checks into code, the
basic mechanism for matching users with roles (groups of
users having specific permissions) is performed entirely at
application deployment time. This provides both greater
flexibility and better security control.
Nikolaos Korfiatis
Dept. of Management & Technology-Athens University of Economics and Business
The Java 2 Enterprise Edition Platform
Summary
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The challenge to IT professionals today is to efficiently
develop and deploy distributed applications for use on both
corporate intranets and over the Internet. Companies that
can do this effectively will gain strategic advantage in the
information economy.
The Java 2 Platform, Enterprise Edition is a standard set of
Java technologies that streamline the development,
deployment, and management of enterprise applications.
The J2EE platform is functionally complete in the sense that
it is possible to develop a large class of enterprise
applications using all the range of technologies that the
java language can provide.
Nikolaos Korfiatis
Dept. of Management & Technology-Athens University of Economics and Business
The Java 2 Enterprise Edition Platform
References & Resources
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http://www.sun.com/developers/evangcentral
SUN Microsystems Technology Evangelists Main Page.
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http://Java.sun.com
The Java Language Reference.
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http://www.maxgoff.com
Max Goff is a Technology Evangelist for Sun Microsystems,
specializing in various Java technology-related topics.
Nikolaos Korfiatis
Dept. of Management & Technology-Athens University of Economics and Business
The Java 2 Enterprise Edition Platform
Java 2 Platform Enterprise Edition(J2EE)
A Model for Enterprise Application Development
Report from the Java Days Conference
Athens,Greece 17/01/2002
Nikolaos Th. Korfiatis
([email protected])
Undergraduate Student
Department of Management Science and Technology
Athens University of Economics and Business
Nikolaos Korfiatis
Dept. of Management & Technology-Athens University of Economics and Business
The Java 2 Enterprise Edition Platform