Java 2 Platform, Enterprise Edition or J2EE is a Standard (albeit with no ISO or ECMA standard) for developing distributed Multi-tier architecture applications, based on modular components running on an application server. It uses several technologies, including JDBC and CORBA, and extends their functionality with Enterprise Java Beans, Java Servlets, Java Server Pages and XML technologies. This allows the developer to create an Enterprise Application that is portable between platforms and scalable, while integrating with several legacy technologies.

General APIs

The J2EE APIs includes several technologies that extend the functionality of the base J2SE APIs.

javax.ejb.*

The Enterprise Java Beans API defines a set of APIs that a distributed object container will support in order to provide persistence, remote communication (using RMI), concurrency control, and access control for distributed objects.

javax.servlet

The Servlets API defines a set of APIs between a web container and a servlet that is responsible for processing requests and issuing responses.

javax.servlet.jsp

The javax.servlet.jsp and javax.servlet.jsp.tagext packages define the JavaServer Pages API.

javax.naming

The javax.naming, javax.naming.directory, javax.naming.event, javax.naming.ldap and javax.naming.spi packages define the Java Naming and Directory Interface (JNDI) API.

java.sql, javax.sql

The java.sql and javax.sql packages define the Java Database Connectivity (JDBC) API

java.transaction.*

These packages define the Java Transaction API (JTA)

javax.xml.*

These packages define the JAXP API

javax.jms.*

These packages define the Java Message Service (JMS) API

Low cost development

One of the benefits of J2EE as a platform is that it is possible to get started with little, or no, expenditure. The J2EE implementation from Sun can be downloaded for free, and there are a great many open source tools available to extend the platform or to simplify development.

Examples of third party open source Java development tools include:

• NetBeans, a Java based integrated development environment
• The Eclipse platform, a Java based integrated development environment
• Jakarta Tomcat, a Servlet/JSP web container
• Jakarta JMeter, a load testing tool for web servers
• Apache Ant, an automated build tool
• JUnit, a framework for automating unit tests
• Jasper Reports, a report writer
• JBoss, an open-source application server
• Geronimo, an open-source application server
• JOnAS, an open-source application server
• Novell exteNd
• Jetty
• Struts, a framework for developing J2EE web applications

Publications

• J2EE Developer's Handbook, 2003 Sam's Publishing. Paul J. Perrone (et al), ISBN 0-672-32348-6

External links

• Sun's J2EE page (http://java.sun.com/j2ee/) - official documentation
• TheServerSide.com (http://www.theserverside.com/) - popular discussion site for J2EE developers

Examples of J2EE application servers include:

• JBoss Application Server (http://www.jboss.org/products/jbossas)
• JOnAS: Java Open Application Server (http://jonas.objectweb.org)
• Geronimo (http://incubator.apache.org/projects/geronimo/)
• Sun Java System Application Server (http://www.sun.com/software/products/appsrvr/home_appsrvr.xml)
• BEA WebLogic (http://bea.com/framework.jsp?CNT=index.htm&FP=/content/products/server/)
• IBM Websphere Application Server (http://www-306.ibm.com/software/webservers/appserv/was/features/)
• Borland Enterprise Server (http://www.borland.com/bes/appserver/)
• More : Certified J2EE servers list (http://java.sun.com/j2ee/compatibility.html)