This article is intended as a quick reference for new Java developers. It defines the acronyms of major Java APIs and technologies and provides a simple overview of what they do.

API: Application Programming Interface. The easiest way to think about an API is that it includes code created for you that you use to write your programs. APIs are organized into packages which have to be imported into your programs so the compiler knows how to define the terms you have used.

AWT: Abstract Windows Toolkit. A package of classes that can be used to make the user interfaces for Applets and applications. It contains the functionality which allows you to add buttons, scroll bars and much more to your programs.

EJB: Enterprise JavaBeans is a component framework for building re-useable, multi-tiered server-side components. This means that it is a development methodology that helps developers break up applications into object-oriented parts and to distribute them and make them available to multiple applications. They are managed by a Bean Container and include session beans, entity beans and message driven beans.

IDL: Interface Definition Language is used to define the interfaces for accessing and operating on objects. This was originally developed by The Object Management Group, but has since grown into other variants including Java IDL and Microsoft IDL. Java IDL is used for invoking CORBA objects via IIOP protocol. (See RMI-IIOP)

J2SE: Java 2 Platform, Standard Edition. This version of the Java platform is also called the SDK (software development kit) or the JDK (Java development kit). It includes development tools, APIs and the installable run-time engine that makes Java programs run. The Standard Edition is the most commonly used version of the Java platform for building client applications, smaller systems and web based applications.