{{Obsolete}}
There is a brief overview of these systems in BPMSummary.
Engines:
jBPM JBoss, LGPL - jBPL
Shark ObjectWeb, LGPL - XPDL
Bonita ObjectWeb, LGPL -XPDL
OSWorkflow OpenSymphony, Apache - proprietary
WfMOpen GPL - proprietary
XFlow GPL - proprietary
Imixs Apache - proprietary
Open Business Engine Apache - proprietary
OpenWFE BSD - proprietary
ODE Apache - BPEL
Editors:
Jawe ObjectWeb, GPL
jForumFusion looks simplistic but is implemented on Hibernate and Spring. Not active currently. Academic Free Licence (ok for us to sell). (5 links)
JavaBB looks good and is an attempt to clone phpBB, again built on Spring, Hibernate and Lucene. Apache Licence. (29 links)
Yazd looks ok. Apache Licence. (537 links)
mvnForum is rich and full of functions and is active. GPL Licence. (1110 links mostly 1 site)
jForum well featured and looking good (like phpBB). BSD Licence. (1570 links)
jGossip new, built with Struts. Mozilla licence. (15 links)
XWiki Code is needs work. (682 links)
JspWiki Core wiki functionality, well structured code, used by ObjectWeb and JBoss. (6,260 links)
SnipSnap Code needs work, but graphing macros are major feature. Lots of other non-core wiki features (e.g. blogging) and seems to getting a high profile (60,200 links)
List here: Issue Management / Bug Tracking