NetBeans IDE
NetBeans IDE is an open source Integerated Development Enviornment supporting a wide range of languages including Java, C++ and Ruby. It is based on Java and can run on almost every platform. There are different editions available - base IDE with standard editor functionality, Java J2SE version with Swing GUI Builder and Java J2EE version which supports Web application development.
NetBeans IDE version 6.0 supports JDK 1.6. It has also extensive support for refactoring, developer collaboration, version control and profiling/debugging.