jared (just another registry editor) is a Java library for editing the Windows registry. It reads a registry file into memory and allows modifications and rewriting of the file. It also contains a command line program for mods using a .reg file. The code supports gcj. jared is particularly appropriate for modifying or analyzing registry hives offline.
jblas is a fast linear algebra library for Java. It is based on BLAS and LAPACK, the de-facto industry standard for matrix computations, and uses state-of-the-art implementations like ATLAS for all its computational routines, making it very fast. It is essentially a lightweight wrapper around the BLAS and LAPACK routines. These packages originated in the Fortran community, which explains their archaic API. On the other hand, modern implementations are hard to beat performance-wise. jblas aims to make this functionality available to Java programmers such that they do not have to worry about writing JNI interfaces and calling conventions of Fortran code.
jcinc is an emulator for the Bell Lab's CARDIAC (Cardboard Illustrative Aid to Computation) computer. A CARDIAC assembler (casm) is included. The CARDIAC kit was published in 1969 to teach the internal workings of a digital computer and machine code programming. jcinc emulates the CARDIAC computer and allows the user to run CARDIAC programs.