A very useful summary of articles and resources available for Jakarta Commons may be found at [http://www.java201.com/resources/browse/70-all.html Java201].
There are currently 4 known books on Jakarta Commons. In order of publication:
[http://www.charlesriver.com/titles/apachejakarta.html Applied Software Engineering Using Apache Jakarta Commons] by Christian Gross (2003-11), Charles River Media.
[http://apress.com/book/bookDisplay.html?bID=246 Pro Jakarta Commons] by Harshard Oak (2004-03), Apress.
[http://www.sourcebeat.com/TitleAction.do?id=4 Jakarta Commons Live] by Jonathan Lehr (coming soon), [SourceBeat].
[http://www.oreilly.com/catalog/jakartackbk/ Jakarta Commons Cookbook] by Tim O'Brien (2004-11 est), O'Reilly.