Eclipse is an Integrated Development Environment (IDE) framework for anything and for nothing in particular, and is one of the most useful tools available to a developer. While its built-in functionality is generic, open, and not of much use by itself, its true value comes from plug-ins you can install along with it. With the appropriate set of plug-ins, you can develop applications in Java and many other programming languages. Plug-ins are available that support development activities ranging from design, through development and debugging, to deployment, of simple and multitiered applications. Many organizations are developing plug-ins for Eclipse and making them available.
Eclipse requires that a Java Runtime Environment (JRE) be installed on your system.