Apache Cocoon is a Web development framework built around the concepts of separation of concerns and component-based Web development. Cocoon implements these concepts around the notion of "component pipelines", each component on the pipeline specializing on a particular operation. This makes it possible to use a Lego(tm)-like approach in building Web solutions, hooking together components into pipelines without any required programming.
Apache Jakarta Regexp is a 100% pure Java regular expression package. Expression syntax supports all of Perl5 syntax, with the exception of back reference substitution markers (several people have mentioned this lack, so please feel free to contribute a solution). It also supports a very limited subset of POSIX features. Performance and features are somewhat inferior to ORO, and the new JDK 1.4 (java.util.regex) package, but the package is especially small and features the ability to precompile expressions (without using object serialization) into byte arrays, thus avoiding the need to load the expression compiler.
Velocity is a Java-based template engine. It permits anyone to use the simple yet powerful template language to reference objects defined in Java code. When Velocity is used for Web development, Web designers can work in parallel with Java programmers to develop Web sites according to the Model-View-Controller (MVC) model, meaning that Web page designers can focus solely on creating a site that looks good, and programmers can focus solely on writing top-notch code. Velocity separates Java code from the Web pages, making the web site more maintainable over the long run and providing a viable alternative to Java Server Pages (JSPs) or PHP. Velocity also provides template services for the Turbine Web application framework, making a template service that allows Web applications to be developed according to a true MVC model.
WSIF (the "Web Services Invocation Framework") is a WSDL-based API for invoking WSDL-described services. WSIF developers interact with Web Services at the abstract level through their WSDL descriptions. This is done independently of APIs specific to a message format or network protocol (eg SOAP APIs). With WSIF, developers work with the same programming model regardless of how the Web service is implemented and accessed.
Avalon is Apache's Java Server Framework project. It is separated into six subprojects: Framework, Excalibur, LogKit, Cornerstone, Phoenix, and Apps. Its purpose is to simplify server side programming for Java-based projects. It formalizes several best practices and patterns for server side programming. Framework describes the interfaces and contracts for the component-based architecture. Excalibur provides a number of useful components and utilities. LogKit is a logging implementation. Cornerstone is a group of reusable server components and services. Phoenix is an enterprise container implementation that uses all of the other subprojects to automatically deploy and manage one or more componentized servers. Apps is a home for several Phoenix-compatible server applications and reusable components (like FtpServer).
Barcode4J is a barcode generation package. The following symbologies are currently implemented: Interleaved 2 of 5, Code 39, Codabar, Code 128, UPC-A and UPC-E (with supplementals), EAN-13 and EAN-8 (with supplementals), EAN-128, POSTNET, Royal Mail Customer Barcode, PDF417, and DataMatrix. Supported output formats are SVG, EPS (Encapsulated PostScript), Bitmap images (such as PNG or JPEG), and Java2D (AWT). Additional features include two APIs (XML-oriented and Bean-style), a Servlet with support for SVG, EPS, and bitmap output, a command-line interface, a demonstration applet, and extensions for Apache Xalan-J, SAXON, and Apache FOP.