J2EE

Introduction to J2EE
Java Platform, Enterprise Edition Version 2 or J2EE is a widely used platform for server programming in the Java programming language. The Java EE Platform differs from the Java Standard Edition Platform (Java SE) in that it adds libraries which provide functionality to deploy fault-tolerant, distributed, multi-tier Java software, based largely on modular components running on an application server.

Nomenclature, standards and specifications
The platform was known as Java 2 Platform, Enterprise Edition or J2EE until the name was changed to Java EE in version 5. The current version is called Java EE 5. The previous version is called J2EE 1.4.
Java EE is defined by its specification. As with other Java Community Process specifications, Java EE is also considered informally to be a standard since providers must agree to certain conformance requirements in order to declare their products as Java EE compliant; albeit with no ISO or ECMA standard.
Java EE includes several API specifications, such as JDBC, RMI, e-mail, JMS, web services, XML, etc, and defines how to coordinate them. Java EE also features some specifications unique to Java EE for components. These include Enterprise JavaBeans, servlets, portlets (following the Java Portlet specification), JavaServer Pages and several web service technologies. This allows developers to create enterprise applications that are portable and scalable, and that integrate with legacy technologies. A Java EE "application server" can handle the transactions, security, scalability, concurrency and management of the components that are deployed to it, meaning that the developers should be able to concentrate more on the business logic of the components rather than on infrastructure and integration tasks.

History
The original J2EE specification was developed by Sun Microsystems.
The J2EE 1.2 SDK was released in December 1999. Starting with J2EE 1.3, the specification was developed under the Java Community Process. Java Specification Request (JSR) 58 specifies J2EE 1.3 and JSR 151 specifies the J2EE 1.4 specification.The J2EE 1.3 SDK was first released by Sun as a beta in April 2001. The J2EE 1.4 SDK beta was released by Sun in December 2002.The Java EE 5 specification was developed under JSR 244 and the final release was made on May 11, 2006.
The Java EE 6 specification has been developed under JSR 316 and is scheduled for release in May, 2009.
General APIs
The Java EE APIs includes several technologies that extend the functionality of the base Java SE APIs.
javax.ejb.*
The Enterprise JavaBean's 1st and 2nd API defines a set of APIs that a distributed object container will support in order to provide persistence, remote procedure calls (using RMI or RMI-IIOP), concurrency control, and access control for distributed objects. This package contains the Enterprise JavaBeans classes and interfaces that define the contracts between the enterprise bean and its clients and between the enterprise bean and the ejb container. This package contains the maximum number of Exception classes (16 in all) in Java EE 5 SDK.
javax.transaction.*
These packages define the Java Transaction API (JTA).
javax.xml.stream
This package contains readers and writers for XML streams. This package contains the only Error class in Java EE 5 SDK.
javax.jms.*
This package defines the Java Message Service (JMS) API. The JMS API provides a common way for Java programs to create, send, receive and read an enterprise messaging system's messages. This package has the maximum number of interfaces (43 in all) in the Java EE 5 SDK.
javax.faces.component.html
This package defines the JavaServer Faces (JSF) API. JSF is a technology for constructing user interfaces out of components.
javax.persistence
This package contains the classes and interfaces that define the contracts between a persistence provider and the managed classes and the clients of the Java Persistence API. This package contains the maximum number of annotation types (64 in all) and enums (10 in all) in the Java EE 5 SDK.
Certified application servers
Java EE 5 certified
· Sun Java System Application Server Platform Edition 9.0, based on the open-source server GlassFish
· GlassFish
· JBoss Application Server Version 5 [1] [2]
· Apache Geronimo 2.0
· Apache OpenEJB via Apache Geronimo
· IBM WebSphere Application Server Community Edition 2.0, based on Apache Geronimo
· IBM WebSphere Application Server V7
· WebLogic Application Server 10.0 from BEA Systems
· Oracle Containers for Java EE 11
· SAP NetWeaver Application Server, Java EE 5 Edition from SAP
· JEUS 6, an Application Server from TmaxSoft
J2EE 1.4 certified
· JBoss 4.x, an open-source application server from JBoss.
· Apache Geronimo 1.0, an open-source application server
· Pramati Server 5.0
· JOnAS, an open-source application server from ObjectWeb
· Oracle Application Server 10g
· Resin, an application server with integrated XML support
· SAP NetWeaver Application Server, Java EE 5 Edition from SAP AG
· Sun Java System Web Server
· Sun Java System Application Server Platform Edition 8.2
· IBM WebSphere Application Server (WAS)
· BEA Systems WebLogic server 8
· JEUS 5 from TmaxSoft