Updated Sept 16 2008: Note that this is not a complete list of Java workflow applications, just the ones that I have found and interest me.

Big, non-open, usually implemented in Java or C++.

Updated: June 20 2008

Galaxia is an activity-based workflow application, where the processes and the workflows are made of dynamic activities that must be completed to finish a task. Contrast this with a procedural system where each step in the process must be completed in order, and the power of this application becomes clear.

The game's a foot.

From the Workflow-NG project page, a list of Drupal 5 modules that integrate with Workflow-NG ( other than Workflow ):

Updated Sept 12 2008: moved page to Home site ( it's a standard, not a project or product ).

See "Links - Business Process Execution Language on the Home site".