Trove provides a free implementation for portions of the Java Collections API. The Trove implementations outperform those provided by Sun by as much as a factor of four, and use less memory. Trove also includes collections for primitives: int->int maps, Object->double maps, float sets, etc.
EJBCA is a fully functional Certificate Authority in Java using JEE technology. It builds on the JEE platform to create a robust, high performance, platform independent, flexible, and component-based CA to be used standalone or integrated in any JEE app. EJBCA comes with a flexible and powerful Web-based admin GUI.
Cheap Threads is a collection of portable C routines for implementing sychronous threads. It includes a scheduler and a facility for passing messages among threads. Threads may run in a round robin or according to a priority scheme. Each thread must voluntarily relinquish control from time so that other threads can run. Since the threads are synchronous, i.e. they don't interrupt each other, they don't need to use semaphores, mutexes, critical sections, or other facilities to keep from interfering with each other. One version of Cheap Threads is designed for embedded systems.
Vstr is a safe and fast string library for C. It is designed for network communication. Its design uses chunks of ptr+length data, so adding, substituting, and deleting data are all fast operations. This model also allows it to do automatic referencing for mmap() areas of memory. Shortcut APIs are included to mmap() a file into a Vstr string, and read()/write() data to/from a Vstr string. Another big feature of the library is a POSIX and ISO 9899:1999 compliant printf() like function, which can also be extended with user supplied formatters that are gcc warning compatible. The total API is over 280 functions, but laid out in a easy to remember manner, including data parsing functions, a non-destructive split() function, and conversion functions (among others).