J2EE (Java 2 Platform, Enterprise Edition) is a Java platform designed for scale computing typical of large enterprises. Sun Microsystems (together with industry partners such as IBM) designed J2EE to simplify application development in a thin client tiered environment. J2EE simplifies application development and decreases the need for programming and programmer training by creating standardized, reusable modular components and by enabling the tier to handle many aspects of programming automatically.
J2EE includes many components of the Java 2 Platform, Standard Edition (J2SE):
- The Java Development Kit (JDK) is included as the core language package.
- Write Once Run Anywhere technology is included to ensure portability.
- Support is provided for Common Object Request Broker Architecture (CORBA), a predecessor of Enterprise JavaBeans (EJB), so that Java objects can communicate with CORBA objects both locally and over a network through its interface broker.
- Java Database Connectivity 2.0 (JDBC), the Java equivalent to Open Database Connectivity (ODBC), is included as the standard interface for Java databases.
- A security model is included to protect data both locally and in Web-based applications.
J2EE also includes a number of components added to the J2SE model, such as the following:
- Full support is included for Enterprise JavaBeans. EJB is a server-based technology for the delivery of program components in an enterprise environment. It supports the Extensible Markup Language (XML)and has enhanced deployment and security features.
- The Java servlet API (application programming interface) enhances consistency for developers without requiring a graphical user interface (GUI)
- Java Server Pages (JSP) is the Java equivalent to Microsoft's Active Server Pages (ASP) and is used for dynamic Web-enabled data access and manipulation.
The J2EE architecture consists of four major elements:
- The J2EE Application Programming Model is the standard programming model used to facilitate the development of multi-tier, thin client applications.
- The J2EE Platform includes necessary policies and APIs such as the Java servlets and Java Message Service (JMS).
- The J2EE Compatibility Test Suite ensures that J2EE products are compatible with the platform standards.
- The J2EE Reference Implementation explains J2EE capabilities and provides its operational definition.