fastutil extends the Java™ Collections Framework by providing type-specific maps, sets, lists and queues with a small memory footprint and fast access and insertion; it also includes a fast I/O API for binary and text files. It is free software distributed under the GNU Lesser General Public License.
ABBYY FineReader Engine for Embedded OS is a highly portable small-footprint OCR SDK with low resource requirements designed to integrate document conversion technologies into the MFPs and other imaging devices
A simple particle system physics engine for processing. I've designed this to be application / domain agnostic. All this is supposed to do is let you make particles, apply forces and calculate the positions of particles over time in real-time. Anything else you need to handle yourself.
Underscore is a utility-belt library for JavaScript that provides a lot of the functional programming support that you would expect in Prototype.js (or Ruby), but without extending any of the built-in JavaScript objects. It's the tie to go along with jQuery's tux, and Backbone.js's suspenders.