J2EE is yet another acronym in the world of computing. This one stands for Java 2 Platform, Enterprise Edition. Its significance will become clear once we trace its lineage. First of all, Java is a programming language developed by Sun Microsystems, one of the giants of the industry. The Java Platform is a virtual machine, a processor look-alike that translates computerized instructions into functions.
The Java language is such that it allows cross-platform communication between multiple kinds of devices. For example, a programmer can develop Java code on a desktop computer and expect it to run on other computers, routers, and even mobile phones, as long as those devices are Java-enabled. This portability is described by the Sun acronym WORA, which stands for "Write once, run anywhere." A large number of mainframes, computers, mobile phones, and other electronic devices operate using the Java Platform.
The 2 in the acronym J2EE stands for Version 2. As with many software applications, J2EE is Java Platform Version 2. Actually, the number 2 is often dropped nowadays, so J2EE becomes Java EE. Traditionally, though, it's still J2EE.
Now, on to the EE. It stands for Enterprise Edition, which is a powerful form of the Java Platform. Sun has created three editions so far. The most precise is the Micro Edition, which is used for mobile phones and PDAs. Following form, this can be abbreviated as Java ME.
The middle edition is the Standard Edition, which can run on mobile devices, laptops and desktop computers. The abbreviated name of this edition is Java SE. Building our way up the pyramid, we come at last to the Enterprise Edition, which includes all the functionality of the Micro Edition and the Standard Edition and also features routines and subroutines designed specifically for servers and mainframes.
One prime benefit of the J2EE, despite the assumption of such a powerful set of source code, is that it is available for free. You can download it right now from the Sun Microsystems website. Third-party open-source tools are available to help you as well, including Apache Tomcat and JBoss. Unless you are running your own multiple-workstation server system or mainframe, however, you are unlikely to encounter or have a need for J2EE. Still, it's good to know what such things stand for.