The setting ExpressionAssignmentHandler is read only on the time of proccess being deployed. So we have two options to work arround this problem. The first is modifing the JpdlXmlReader soruce file, replace "org.jbpm.identity.assignment.ExpressionAssignmentHandler" with your implemented class name, then rebuild the jbpm-XXX.jar. The most important step is to re-install the process designer in Eclipse so that when you depoly a process, your ExpressionAssignmentHandler class name will be saved into the table JBPM_DELEGATION. The other approach is more simple: issue the following SQL updat statement after deployment: update JBPM_DELEGATION set CLASSNAME_ = 'FULL_CLASSE_NAME_OF_YOUR_EXPRESSION_HANDLER' View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4000789#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...