J2EE
(Java 2 Platform, Enterprise Edition) A platform from Sun for building distributed enterprise applications. J2EE services are performed in the middle tier between the user's machine and the enterprise's databases and legacy information systems. J2EE comprises a specification, reference implementation and set of testing suites. Its core component is Enterprise JavaBeans (EJBs), followed by JavaServer Pages (JSPs) and Java servlets and a variety of interfaces for linking to the information resources in the enterprise.
The J2EE interfaces include JDBC for databases, JNDI for directories, JTA for transactions, JMS for messaging, JavaMail for e-mail systems and JavaIDL for CORBA connectivity. Java Connectors are interfaces to a variety of legacy applications. In December 1999, J2EE Version 1.2 was introduced as the first formal release of the specification.
From J2EE to Java EE
In 2005, Sun renamed the Java Platform by dropping the 2. thus J2EE 5.0 became Java EE 5.0. See EJB, JSP, servlet, Java Connector, Java 2 and J2ME.
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| Pure J2EE Environment |
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| This is a fully compliant J2EE Web server and application server environment showing the interfaces to all information sources in the enterprise. This is an "ideal" Java-only deployment. In practice, other server-side scripts and applications may be used as in the illustration below. |
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| Mixed Environment |
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| In practice, Web servers and application servers use a variety of server-side processing techniques. This illustration depicts the various methods. |