GNUstep is a free software implementation of the Cocoa (formerly OpenStep) Objective-C frameworks, widget toolkit, and application development tools for Unix-like operating systems and Microsoft Windows. It is part of the GNU Project.GNUstep features a cross-platform, object-oriented IDE. Like Apple Cocoa, GNUstep also has a Java interface, as well as Ruby, Guile and Scheme bindings. The GNUstep developers track some additions to Apple's Cocoa to remain compatible.