Netbeans - NetBeans IDE 7.0. Develop desktop, mobile and web applications with Java, PHP, C/C++ and more. Runs on Windows, Linux, Mac OS X and Solaris. NetBeans IDE is open-source and free.
Eclipse - Eclipse is an open source community, whose projects are focused on building an open development platform comprised of extensible frameworks, tools and runtimes for building, deploying and managing software across the lifecycle.
IntelliJ IDEA - Capable and Ergonomic IDE for JVM
BlueJ - BlueJ is an Integrated Development Environment for Java, developed mainly for educational purposes...
Xcode - Xcode is Apple’s powerful integrated development environment for creating great apps for Mac, iPhone, and iPad. Xcode 4 includes the Xcode IDE, instruments, iOS Simulator, and the latest Mac OS X and iOS SDKs.
Aptana Studio - The world’s most powerful open-source web development IDE just got better. Rebuilt from the ground-up. It's now much faster, customizable and includes new features to help you be more productive.