JAva DIstributed Framework provides a secure and flexible Framework for distributed grid and volunteer computing applications (separate client & server Framework). For more informations take a look at the project page http://jadif.sourceforge.net
Ex-Crawler is divided into 3 subprojects (Crawler Daemon, distributed gui Client, (web) search engine) which together provide a flexible and powerful search engine supporting distributed computing. More informations: http://ex-crawler.sourceforge.net