JStart gives the ability to start Java class files (or applets) by double clicking on them from the desktop like any executable program. You only have to assign *.class files to this program. It loads a class file, investigates it according to the Java Sun class file specification, extracts the full class name (including packages), and invokes the main method of that class.
Libxml2 is the XML C library developed for the Gnome project. The library code is portable (to Linux, Unix, Windows, embedded systems, etc.) and modular; most of the extensions can be compiled out. Libxml2 implements a number of existing standards related to markup languages, including the XML standard, Namespaces in XML, XML Base, Relax NG, RFC 2396, XPath, XPointer, HTML4, XInclude, SGML Catalogs, and XML Catalogs. In most cases, libxml tries to implement the specifications in a relatively strict way. To some extent, it provides support for the following specifications, but doesn't claim to implement them: DOM, FTP client, HTTP client, and SAX2. Support for W3C XML Schemas is in progress. It includes xmllint, a command line XML validator.
PLWM (The Pointless Window Manager) is a highly modularised window manager written in Python. It has no configuration files; instead, you combine Python classes to make the perfect window manager for yourself. This is not a window manager for non-programmers. The feature list includes point-to-focus and sloppy-focus, outline move, resizing, deiconifying, views (extremely powerful workspaces), and multihead support. PLWM is controlled completely from the keyboard.