Here's a partial list of projects and users of Jython (most recent additions first). If you are aware of any others, or would like to get your projects listed here, just drop us a message at firstname.lastname@example.org.
[http://staf.sourceforge.net/index.php STAF (Software Testing Automation Framework)] uses Jython for its execution engine <a href="http://staf.sourceforge.net/index.php#STAXOverview">STAX</a>.
[http://drools.org Drools] An expert system written in java with semantics for Python. You can use valid Python syntax for any condition or consequence. With drools you can easily process large amounts of data with logic and data separation, leaving your customers to concentrate just on the business rules and not how to process the data You just insert the facts into the system and drools executes the consequences on those facts based on the conditions
[http://www.jpk.com JPK Instruments] JPK Instruments is a young biotech company in Berlin that develops atomic force microscopes for use in biological and soft-matter research. The instrument control and imaging software is written mainly in Java and Jython. Jython allows JPK's customers to write scripts to automate their experiments, provides a command-line interface for debugging and for accessing experimental features, and for dynamically configuring the standard software.
[http://www.cabochon.com Wyvern] Wyvern is a 100% free, extensible, multi-player online adventure game that uses Jython as its extension language. You can become a Wizard player and develop new game areas and objects using Jython.
[http://www.free-schooling.org FreePlay] The Freeplay project is developing a free course authoring tool which can be used to create lessons which are more like adventure games than school lessons. Jython is used as the scripting language.
[http://www.propylon.com Propylon] Propylon use Jython to bring the power of Python to complex XML processing on the Java Virtual Machine. Propylon also use Jython to provide enhanced server-side scripting and integration in its pervasive portal server product: Mission Control.
[http://www.AirportTools.com/jsimmod JSIMMOD] JSIMMOD is a free simulation tool which is bringing advanced concepts to the modeling of aviation issues. Jython provides dynamic elements to the simulation which are not easily replicated in other simulations.
[http://www.pushtotest.com/ptt TestMaker] A free open-source framework for building intelligent test agents to check Web Services (HTTP, HTTPS, SOAP, .NET, XML-RPC) for functionality, scalability and performance. TestMaker embeds Jython as a scripting language that calls a library of test objects. TestMaker is built on NetBeans so it offers Jython users a very nice graphical integrated development environment for general Jython development too.
[http://www.bison-group.com BISON Solution] BISON Solution is the first process oriented Business Solution developed in 100% pure Java and fulfilling the J2EE Standards. BISON Solution uses Jython for scripting and high-level customizing of existing business objects.
[http://www.ssec.wisc.edu/~billh/visad.html VisAD] VisAD is a Java component library for interactive and collaborative visualization and analysis of numerical data. It uses Jython to define an easy-to-use scripting language.
[http://luxor-xul.sourceforge.net Luxor] Luxor is an open-source XML User Interface Language (XUL) toolkit in Java that supports handpicked Mozilla XUL goodies and includes a web server, a portal engine (supporting RSS), a template engine (Velocity), a scripting interpreter (Python) and more.