SableCC is a parser generator that generates fully featured object-oriented frameworks for building compilers, interpreters, and other text parsers. In particular, generated frameworks include intuitive strictly-typed abstract syntax trees and tree walkers. SableCC also keeps a clean separation between machine-generated code and user-written code, which leads to a shorter development cycle.
Tapestry is a rich, component-based object model for developing dynamic, robust, highly interactive Web applications. Applications are constructed in terms of Java objects, methods and properties, instead of URLs and query parameters. It builds and interprets all URLs, dispatching directly to application-specific "listener" methods. It includes complete source code, documentation, tutorials and a complete example J2EE application.
Apache SpamAssassin is an extensible email filter that is used to identify spam. Once identified, the mail can then be optionally tagged as spam for later filtering. It provides a command line tool to perform filtering, a client-server system to filter large volumes of mail, and Mail::SpamAssassin, a set of Perl modules allowing Apache SpamAssassin to be used in a wide variety of email systems.
The Apache Open For Business Project is an enterprise automation software project that includes ERP, CRM, E-Business/E-Commerce, SCM, MRP, and CMMS/EAM functions. It is a foundation and starting point for enterprise solutions and can certainly be used out of the box, but is also great for creating specialized applications.