Hi, I'm posting in this list because I will post very low level details which may not fit well in the user list. Please tell me if this is correct. We are trying to build a system using JBPM with human task, and we are now using the recent LocalTaskService and LocalHTWorkItemHandler ... that way: humanTaskClient = new LocalTaskService(taskService); .... LocalHTWorkItemHandler localHTWorkItemHandler = new LocalHTWorkItemHandler(humanTaskClient, sesion); .... We are facing a NullpointerException when unmarshalling the result of a completed human task. Here's the relevant stack trace: 11:11:21,734 ERROR [stderr] (http--0.0.0.0-8080-1) java.lang.NullPointerException 11:11:21,734 ERROR [stderr] (http--0.0.0.0-8080-1) at org.jbpm.marshalling.impl.ProtobufProcessMarshaller.unmarshallVariableValue(ProtobufProcessMarshaller.java:270) 11:11:21,734 ERROR [stderr] (http--0.0.0.0-8080-1) at org.jbpm.task.utils.ContentMarshallerHelper.unmarshall(ContentMarshallerHelper.java:112) 11:11:21,750 ERROR [stderr] (http--0.0.0.0-8080-1) at org.jbpm.process.workitem.wsht.GenericHTWorkItemHandler$TaskCompletedHandler.handleCompletedTask(GenericHTWorkItemHandler.java:230) 11:11:21,750 ERROR [stderr] (http--0.0.0.0-8080-1) at org.jbpm.process.workitem.wsht.GenericHTWorkItemHandler$TaskCompletedHandler.execute(GenericHTWorkItemHandler.java:204) 11:11:21,750 ERROR [stderr] (http--0.0.0.0-8080-1) at org.jbpm.task.service.local.LocalTaskService$SimpleEventTransport.trigger(LocalTaskService.java:320) 11:11:21,750 ERROR [stderr] (http--0.0.0.0-8080-1) at org.jbpm.task.event.MessagingTaskEventListener.taskCompleted(MessagingTaskEventListener.java:80) 11:11:21,765 ERROR [stderr] (http--0.0.0.0-8080-1) at org.jbpm.task.event.TaskEventSupport.fireTaskCompleted(TaskEventSupport.java:46) 11:11:21,765 ERROR [stderr] (http--0.0.0.0-8080-1) at org.jbpm.task.service.TaskServiceSession.postTaskCompleteOperation(TaskServiceSession.java:563) 11:11:21,765 ERROR [stderr] (http--0.0.0.0-8080-1) at org.jbpm.task.service.TaskServiceSession.taskOperation(TaskServiceSession.java:495) 11:11:21,765 ERROR [stderr] (http--0.0.0.0-8080-1) at org.jbpm.task.service.local.LocalTaskService.complete(LocalTaskService.java:82) Some inspection lead us to locate this snippet that is ObjectMarshallingStrategyStore objectMarshallingStrategyStore = marshallingConfigurationImpl.getObjectMarshallingStrategyStore(); context = new MarshallerReaderContext(stream, null, null, objectMarshallingStrategyStore, null, env); if(classloader != null){ context.classLoader = classloader; }else{ context.classLoader = ContentMarshallerHelper.class.getClassLoader(); } ExtensionRegistry registry = PersisterHelper.buildRegistry( context, null ); Header _header = PersisterHelper.readFromStreamWithHeader(context, registry); Variable parseFrom = JBPMMessages.Variable.parseFrom(_header.getPayload(), registry); Object value = ProtobufProcessMarshaller.unmarshallVariableValue(context, parseFrom); which is radically different from the previous implementation ( protocol buffers appears ). The problem is that in this code ( in ProtobufProcessMarshaller ) : ObjectMarshallingStrategy strategy = context.usedStrategies.get( _variable.getStrategyIndex() ); Object value = strategy.unmarshal( context.strategyContexts.get( strategy ), context, _variable.getValue().toByteArray(), (context.ruleBase == null)?null:context.ruleBase.getRootClassLoader() ); return value; context.usedStrategies and context.strategyContexts are both Maps of size 0. And so the NPE. Our process runs ok before creating the human task and it only fails when completing a human task. Any insight on what can be happening here? Greets, Alberto R. Galdo argaldo(a)gmail.com