GNUstep is a cross-platform, object oriented environment composed of frameworks, tools, and servers (daemons). It is very similar to the Cocoa frameworks from Apple, and tries to maintain compatibility with Cocoa wherever it is desired and possible. The frameworks provide classes for containers, distributed objects, object archiving, file management, text system, font management, image composition, WYSIWYG PostScript graphics, and more.
GPP is a general-purpose preprocessor with customizable syntax, suitable for a wide range of preprocessing tasks. Its independence from any programming language makes it much more versatile than cpp, while its syntax is lighter and more flexible than that of m4. The syntax is fully customizable, which makes it possible to process text files, HTML, or source code equally efficiently in a variety of languages.
JIGS (Java Interface for GnuStep) allows Java programmers to use the GNUstep libraries from Java, but it is more than a set of bindings for GNUstep from Java: it 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). Moreover, JIGS can generate automatically wrappers for your own Objective-C GNUstep libraries.
SLOCCount is a suite of programs for counting physical source lines of code (SLOC) in possibly large software systems. It can count physical SLOC for a wide number of languages. It can take a large set of files and automatically categorize their types using a number of different heuristics, and also comes with analysis tools.
jGRASP integrates the Control Structure Diagram (CSD) seamlessly and unobtrusively into source-code editing for Java, C, C++, Objective-C, Ada, and VHDL. The CSD is a control flow and data structure diagram that fits into the space normally taken by indentation in source code. Its intention is to improve the readability of source code. The CSD also enables source code folding in a meaningful way, based on code structures. jGRASP provides lots of editing features, an integrated Java debugger, UML dependency diagrams for Java, configurable colors and font size, and click-to-error for compile and runtime (Java stack dumps) errors.
OO Bench compares the speed of the same object-oriented tasks in several object-oriented languages. C++, Objective-C, and Java are currently supported. Support for Smalltalk, CLOS, CSharp, and Eiffel are in development. It aims to be simple, easy to understand, and easy to port. It also aims to follow the idioms and best practices advised by each language as much as possible. It is designed to make it easy to look up how a particular problem is best solved in another language.