Wooi Joe Chuah [https://community.jboss.org/people/joe.chuah] created the discussion "Calling workItemManager.completeWorkItem() on a dynamicSubProcess results in NPE & root cause" To view the discussion, visit: https://community.jboss.org/message/779240#779240 -------------------------------------------------------------- Hi, I've been bugged by this stack trace for a long time now whenever a dynamicSubProcess created by the DynamicUtils is terminated. Caused by: java.lang.NullPointerException     at org.jbpm.workflow.instance.node.SubProcessNodeInstance.handleOutMappings(SubProcessNodeInstance.java:192)     at org.jbpm.workflow.instance.node.SubProcessNodeInstance.processInstanceCompleted(SubProcessNodeInstance.java:185)     at org.jbpm.workflow.instance.node.SubProcessNodeInstance.signalEvent(SubProcessNodeInstance.java:173)     at org.jbpm.workflow.instance.impl.WorkflowProcessInstanceImpl.signalEvent(WorkflowProcessInstanceImpl.java:344)     at org.jbpm.process.instance.event.DefaultSignalManager.internalSignalEvent(DefaultSignalManager.java:81)     at org.jbpm.process.instance.event.DefaultSignalManager$SignalAction.execute(DefaultSignalManager.java:181)     at org.drools.common.AbstractWorkingMemory.executeQueuedActions(AbstractWorkingMemory.java:976)     ... 96 more After tracing the code, I've found the root cause which is located at org.jbpm.workflow.core.node.SubProcessNode public List<DataAssociation> getOutAssociations() {     return Collections.unmodifiableList(this.outMapping); } the outMapping attribute of the dynamicSubProcess is null hence calling Collections.unmodifiableList(+null+) will hit a NPE. Since SubProcessNodeInstance.java:192 (handleOutMappings) expects a Collection object to be returned, I suggest returning an empty list if the outMapping is null. If anyone would be so helpful to implement a fix for this I'd be very greatful :) no more ugly stacktraces after completing the process. Thanks -------------------------------------------------------------- Reply to this message by going to Community [https://community.jboss.org/message/779240#779240] Start a new discussion in jBPM at Community [https://community.jboss.org/choose-container!input.jspa?contentType=1&...]