JIGS stands for Java Interface for GnuStep. It is a package allowing integration between Java and Objective-C. The main purpose of JIGS is to allow Java programmers to use the GNUstep libraries from Java.
JIGS is more than a set of bindings for GNUstep from Java; JIGS takes advantage of the fact that Objective-C and Java are very similar languages to make it possible to use Objective-C classes from Java using exactly the same API (and vice versa). You have to learn the GNUstep API only once, and then you can use it both from Objective-C and from Java in the same way! Moreover, JIGS can generate automatically wrappers for your own Objective-C GNUstep libraries.
JIGS allows you to write optimized classes and components in Objective-C, and make them available to Java developers. In the typical configuration, fast Objective-C components and libraries are used in the backend, and JIGS is used to integrate them smoothly in a Java front-end. Moving from one language to the other is as easy as it can possibly be with two different languages.
JIGS is free software and part of the GNU project, freely available from the Free Software Foundation under the GNU LGPL license.
This manual does not cover getting and installing JIGS; please refer to the GNUstep web page for more information on getting and installing JIGS.