Hello, SidKennedy is my project partner and I have the same problem with this exception in a slightly different context. @kukeltje To answer your Question, yes, the Tool declaration is somewhere else. I think the point is, that there is the XML action configuration that cannot be parsed in some kind of way. But I don't understand why. As I remember from the user guide, there is no xml schema or something like that that has to be validated when inserting the configuration inside of an action declaration in the jPDL. Here is my action declaration: <task-node name="Big Step1"> | <task name="design modeling"> | <event type="task-create"> | <action class="org.sureal_projekt.spms.assignment.ResourceAssignmentHandler"> | <resourceHooks> | <role group="PIM" /> | <material group="PIM.design" /> | <tool group="PIM.design" /> | </resourceHooks> | </action> | </event> | </task> | <transition name="design modeling completed" to="Big Step2"></transition> | </task-node> And here is my Exception: 18:31:31,265 ERROR [FieldInstantiator] couldn't parse set field 'resourceHooks' to value '<resourceHooks xmlns="urn:jbpm.org:jpdl-3.2"> | <role group="PIM"/><material group="PIM.design"/><tool group="PIM.design"/></resourceHooks>' | java.lang.NullPointerException | at org.jbpm.instantiation.FieldInstantiator.setPropertyValue(FieldInstantiator.java:70) | at org.jbpm.instantiation.FieldInstantiator.instantiate(FieldInstantiator.java:61) | at org.jbpm.instantiation.Delegation.instantiate(Delegation.java:163) | at org.jbpm.instantiation.Delegation.getInstance(Delegation.java:125) | at org.jbpm.instantiation.Delegation$$FastClassByCGLIB$$6bae1598.invoke(<generated>) | at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149) | at org.hibernate.proxy.CGLIBLazyInitializer.intercept(CGLIBLazyInitializer.java:161) | at org.jbpm.instantiation.Delegation$$EnhancerByCGLIB$$c441f5db.getInstance(<generated>) | at org.jbpm.graph.def.Action.execute(Action.java:122) | at org.jbpm.graph.def.GraphElement.executeAction(GraphElement.java:235) | at org.jbpm.graph.def.GraphElement.executeActions(GraphElement.java:212) | at org.jbpm.graph.def.GraphElement.fireAndPropagateEvent(GraphElement.java:182) | at org.jbpm.graph.def.GraphElement.fireEvent(GraphElement.java:166) | at org.jbpm.taskmgmt.exe.TaskInstance.create(TaskInstance.java:169) | at org.jbpm.taskmgmt.exe.TaskMgmtInstance.createTaskInstance(TaskMgmtInstance.java:144) | at org.jbpm.graph.node.TaskNode.execute(TaskNode.java:167) | at org.jbpm.graph.def.Node.enter(Node.java:316) | at org.jbpm.graph.def.Node$$FastClassByCGLIB$$d187eeda.invoke(<generated>) | at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149) | at org.hibernate.proxy.CGLIBLazyInitializer.intercept(CGLIBLazyInitializer.java:161) | at org.jbpm.graph.def.Node$$EnhancerByCGLIB$$af21a19d.enter(<generated>) | at org.jbpm.graph.def.Transition.take(Transition.java:119) | at org.jbpm.graph.def.Node.leave(Node.java:383) | at org.jbpm.graph.node.StartState.leave(StartState.java:70) | at org.jbpm.graph.def.Node$$FastClassByCGLIB$$d187eeda.invoke(<generated>) | at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149) | at org.hibernate.proxy.CGLIBLazyInitializer.intercept(CGLIBLazyInitializer.java:161) | at org.jbpm.graph.def.Node$$EnhancerByCGLIB$$af21a19d.leave(<generated>) | at org.jbpm.graph.exe.Token.signal(Token.java:174) | at org.jbpm.graph.exe.Token.signal(Token.java:145) | at org.jbpm.graph.exe.Token$$FastClassByCGLIB$$74df1c6e.invoke(<generated>) | at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:149) | at org.hibernate.proxy.CGLIBLazyInitializer.intercept(CGLIBLazyInitializer.java:161) | at org.jbpm.graph.exe.Token$$EnhancerByCGLIB$$5bb04831.signal(<generated>) | at org.jbpm.graph.exe.ProcessInstance.signal(ProcessInstance.java:241) My Declaration of the invoked ResourceAssignmentHandler is very long, so I would like to avoid posting it here. :) But as I said, I think, that's not the point. And as SidKennedy wrote, the code that is invoked by the action does work very well. There is only THIS Exception, that crashes my web application. Do you have any idea what the problem might be? Thanks in advance. lou View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4104721#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...