Eclipse is an integrated development environment used for computer programming. It is, in fact, the most widely used Java integrated development environment, comprising a base workspace and extensible plugin system which allows users to customize the environment they're creating. Eclipse is primarily used to develop Java apps and is written almost entirely in Java.
The NetBeans Platform makes it relatively simple to develop applications from a set of modular software components, or modules. NetBeans is a software development platform that is written in Java. Third party developers can extend applications based on NetBeans, including those from its integrated development environment. The NetBeans integrated development environment supports various programming languages including PHP, C/C++, and HTML5, but it is intended first and foremost for Java development.
As a Java integrated development environment, IntelliJ IDEA is used to develop computer software. IntelliJ is available as a proprietary commercial edition and an Apache 2 licensed community edition, both of which can be used for commercial development.