J2EE Tutorial

( Day-1 )

authored by

Biswabrata Banerjee

Introduction to

...few words about JAVA

Over the last few years, the Java language has been significantly improved. While

the core architecture of Java remained the same, the language has been enhanced in

terms of security, usability of APIs, etc. Today, there are three major editions of Java

technologies, as follows:

1. Java 2 Standard Edition (J2SE): Also referred to as Java Development Kit

(JDK). J2SE is a software development kit that includes a set of APIs, tools, and

a runtime for developing general-purpose applications.

2. Java 2 Enterprise Edition (J2EE): J2EE is the basis for Java-based enterprise

applications . J2EE specifies a standard for developing multi-tier distributed

component-based applications. J2EE provides an integrated technical framework

for developing Internet-enabled enterprise, and e-commerce applications.

3. Java 2 Micro Edition (J2ME): J2ME provides a lightweight and optimized

Java environment for applications and consumer and mobile devices.

area of Interest J2EE

What we are going to learn in this session(1) ?

- The J2EE technology components

- J2EE architecture overview

- J2EE containers

About J2EE Technology

J2EE is essentially a specification that stipulates how the various

J2EE technologies work together . According to use, The collection of J2EE

technologies can be divided into the following three :

The component technologies:

Used to hold business logic. There are three type of

components: Servlets, JSP pages and EJBs.

The service technologies:

Used to provide the application components with

supported services to function efficiently.

The communication technologies:

Used to communicate among the different parts of

the application ,whether they are local or remote.

With any application, the most important element is modeling the necessary business logic through components or application level reusable units. The J2EE platform provides the following technologies for developing components:

WEB Components:

Servlets :

-server-side programs that allow application logic to be embedded in HTTP request-response process.

-enable dynamic content in HTML,XML.

Java Server Pages (JSP Pages):

-Text-based documents that separates the application logic from presentation logic.

Enterprise Java Bean Components(EJBs):

Used for developing distributed components.

COMPONENT TECHNOLOGIES

SERVICE TECHNOLOGIES

J2EE is essentially a specification that stipulates how the various

J2EE technologies work together. J2EE service technologies include:

Java Naming and Directory Interface (JNDI):

Used for naming and directory

Java Message Service (JMS):

Used for asynchronous messaging

Java Transaction API (JTA):

Used for distributed transactions

Java Database Connectivity (JDBC) :

Used for enterprise-level database access

Java API for XML Parsing (JAXP):

Used for parsing XML documents

Java Connector Architecture (JCA):

Using for a variety of legacy application

Java Authentication and Authorization Services (JAAS):

Used for providing a means to grant permissions

based on who is executing the code.

Java Mail:

Used for sending and receiving electronic mail

COMMUNICATION TECHNOLOGIES

This group holds those technologies that ‘glue’ together the

application and let the various components and services to communicate

with each-other .It includes : Internet Protocols ( HTTP,TCP/IP, SSL) ,

Remote Object protocols (RMI, RMI-IIOP).

J2EE architecture

database

BrowserApplet container

app. client

container

Client Machine

Web container

EJB container

servletJSP page

Enterprise Bean

J2EE server

J2EE Server and Containers

app. client

Continue…

Q. What is a container anyway ?!

A: A J2EE container is a runtime to manage application components developed

according to the API specification and to provide access to the J2EE APIs.

The container architecture shown in the previous slide has four containers:

A web container for hosting Java servlets and JSP pages.

A EJB container for hosting Enterprise Java Bean Components.

An applet container for hosting java applets.

An Application client container for hosting standard Java application

Next class

JSP and MVC