1. J2EE Application Development
B.Ramamurthy
11/19/2018

2. Introduction
We will show how to develop, deploy and run a simple client-server application that consists of a currency converter enterprise bean and two clients: a J2EE client and a web client that consists of a JSP page.
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3. The Setup
Source code from
Get the J2EE1.3 from
Get the “ant” build tool from Jakarta. This is similar to “make” utility of unix.
Setup the environment variables:
JAVA_HOME: location of J2SE installation
J2EE_HOME: location of J2EE installation
ANT_HOME: location of ant installation
PATH : include “bin” directories of J2EE, J2SE and ant installation
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4. Starting the Server
J2EE server is a web server, servlet server and also an application server.
You start it by
j2ee –verbose
You stop the server by
J2ee -stop
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5. Deployment Has two modes: command line and GUI interface.
In the case of GUI tool you create an “ear” file and the drop the component modules into this “ear” (enterprise archive) file.
In the case of command line you will make the components first and then assemble them into an “ear” file.
To start a deploy tool
deploytool
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6. Application source code
An enterprise bean which represents the business logic of an application:
Remote interface: defines the business methods that a client may call.
Home interface: defines the methods to create, find or remove an enterprise bean.
Enterprise bean class: implements the two interfaces and also callbacks for containers.
Our application is called “converter”. Lets study the code representing these files.
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7. Compiling the Source code
The compile targets for this tutorial are available in a file build.xml.
You compile the “converter” java files by
ant converter
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8. Packaging For this example, “ear” file will be: ConverterApp.ear
This file will contain: EJB JAR file, Web client’s WAR file and Application clients JAR file/class file
Deploytool helps in configuring and packaging each component. It automatically creates the deployment descriptor.
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9. Packaging the enterprise bean
Add the classes that make the bean component: Converter.class, ConverterBean.class, ConverterHome.class to the “jar”
Specify properties: bean type (session, entity, etc.), transactions etc. The deploytool has various tabs and support to specify these.
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10. Application Client
Written in Java. Can run on any Java runtime (need not be J2EE).
In this application client requires two JAR files: JAR file for the J2EE containing client’s deployment descriptor and its class files, and the second JAR files containing stub classes required at run time by the client.
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11. Application Client (contd.) and Web Client
Basic tasks performed by the client of an enterprise bean:
Locating the home interface
Creating an enterprise bean instance
Invoking a business method
Deploytool:
Creates client’s deployment descriptor
Puts deployment descriptor and client code into a JAR file
Add the JAR file to the applications ConverterApp.ear file
We use JSP for this purpose: contains the same tasks as the application client plus web display elements.
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12. Deployment and Running the Clients
JNDI: We also specify JNDI names using the deploytool.
Tools  deploy of the tool.
runclient etc. to run from command line
Webclient:
11/19/2018