Release 2.2 of Sat4j contains a new and faster explanation engine that ships with Eclipse 3.6.

The Pseudo-Boolean library provides now Weighted Boolean Optimization capability as defined in the Pseudo-Boolean Evaluation 2010. It also provides a new parallel Pseudo-Boolean solver that generally improves optimization time.

The MaxSat solver has received a lot of attention since release 2.1, and has been fine tuned over the months to deliver our best MaxSat solver so far.

A detailed description of release 2.2 has been published in the JSAT journal:
Daniel Le Berre and Anne Parrain. The Sat4j library, release 2.2. JSAT Volume 7 (2010), system description, pages 59-64
http://jsat.ewi.tudelft.nl/content/sd/JSAT7_4_LeBerre.pdf

People willing to cite Sat4j in a scientific paper are invited to use that reference instead of using the URL of the project.

A presentation focusing on the parallel Pseudo-Boolean solver and the MaxSat solver is available here:
http://www.satcompetition.org/PoS/presentations-pos/leberre.pdf