libAstronomy provides a set of astronomical routines to ease the calculation of ephemerides. It includes mathematical functions to compensate various astronomical phenomena like precession, nutation, etc. The getconstellation routine finds the constellation for a given coordinate. It also calculates the positions of the sun and moon in two different precise ways.
The keeper library provides a simple-to-use C interface for reading and writing configuration data. The data is stored in text files in a hierarchical system. The concept is not dissimilar to that of the Windows registry, but the interface is much cleaner. The library comes with both a command line program and a GUI program for examining and modifying the keeper database.
jUSB contains Java source code for a USB development library with some basic USB tools. It is built on top of the Linux "usbfs" facility. It has both an API (for applications) and an SPI (used by Linux and RMI providers). The API is demonstrated by three bundled utilities or sample applications, and by http://jPhoto.sourceforge.net (for digital camera access).
jQKat is a simple Java class to obtain data from the free RadioShack CueCat(tm) bar code reader in standard format. It returns a String of the actual bar code data. It has been tested against many books and routine household products. It can also decode strings that have already been received from the CueCat reader.
JDxpc is a reimplementation of dxpc (the Differential X Protocol Compressor) in pure Java. It is an X protocol compressor designed to improve the speed of X applications run over low-bandwidth links (such as dialup PPP connections). JDxpc encrypts the compressed data stream in SSL.