[jboss-user] [jBPM] - XOR Gateway

tmmaluleke [https://community.jboss.org/people/tmmaluleke] created the discussion "XOR Gateway" To view the discussion, visit: https://community.jboss.org/message/764516#764516 -------------------------------------------------------------- Hello, I have a project which have the XOR gateway en when I run it its gives me this error: This is what I coded in my XOR gateway: if(studentId !="null"); the process must continue or if(studentId =="null"); the process must alert the user to input the studentId. but when I run this error occurs. Exception in thread "Thread-4" org.jbpm.workflow.instance.WorkflowRuntimeException: [validatingStudentId.bpmn:1 - Gateway:5] -- Exception when trying to evaluate constraint Accept in split Gateway     at org.jbpm.workflow.instance.impl.NodeInstanceImpl.trigger(NodeInstanceImpl.java:130)     at org.jbpm.workflow.instance.impl.NodeInstanceImpl.triggerNodeInstance(NodeInstanceImpl.java:205)     at org.jbpm.workflow.instance.impl.NodeInstanceImpl.triggerCompleted(NodeInstanceImpl.java:164)     at org.jbpm.workflow.instance.impl.ExtendedNodeInstanceImpl.triggerCompleted(ExtendedNodeInstanceImpl.java:47)     at org.jbpm.workflow.instance.node.StateBasedNodeInstance.triggerCompleted(StateBasedNodeInstance.java:162)     at org.jbpm.workflow.instance.node.StateBasedNodeInstance.triggerCompleted(StateBasedNodeInstance.java:143)     at org.jbpm.workflow.instance.node.WorkItemNodeInstance.triggerCompleted(WorkItemNodeInstance.java:239)     at org.jbpm.workflow.instance.node.HumanTaskNodeInstance.triggerCompleted(HumanTaskNodeInstance.java:90)     at org.jbpm.workflow.instance.node.WorkItemNodeInstance.workItemCompleted(WorkItemNodeInstance.java:301)     at org.jbpm.workflow.instance.node.WorkItemNodeInstance.signalEvent(WorkItemNodeInstance.java:277)     at org.jbpm.workflow.instance.impl.WorkflowProcessInstanceImpl.signalEvent(WorkflowProcessInstanceImpl.java:326)     at org.drools.process.instance.impl.DefaultWorkItemManager.completeWorkItem(DefaultWorkItemManager.java:116)     at org.jbpm.process.workitem.wsht.GenericHTWorkItemHandler$TaskCompletedHandler.handleCompletedTask(GenericHTWorkItemHandler.java:221)     at org.jbpm.process.workitem.wsht.GenericHTWorkItemHandler$TaskCompletedHandler$1.run(GenericHTWorkItemHandler.java:187)     at java.lang.Thread.run(Unknown Source) Caused by: java.lang.RuntimeException: Exception when trying to evaluate constraint Accept in split Gateway     at org.jbpm.workflow.instance.node.SplitInstance.internalTrigger(SplitInstance.java:79)     at org.jbpm.workflow.instance.impl.NodeInstanceImpl.trigger(NodeInstanceImpl.java:124)     ... 14 more Caused by: java.lang.RuntimeException: unable to execute ReturnValueEvaluator     at org.jbpm.process.instance.impl.ReturnValueConstraintEvaluator.evaluate(ReturnValueConstraintEvaluator.java:130)     at org.jbpm.workflow.instance.node.SplitInstance.internalTrigger(SplitInstance.java:72)     ... 15 more Caused by: java.lang.RuntimeException: Constraints must return boolean values: if(studentId !=" null"); returns null     at org.jbpm.process.instance.impl.MVELReturnValueEvaluator.evaluate(MVELReturnValueEvaluator.java:119)     at org.jbpm.process.instance.impl.ReturnValueConstraintEvaluator.evaluate(ReturnValueConstraintEvaluator.java:128)     ... 16 more -------------------------------------------------------------- Reply to this message by going to Community [https://community.jboss.org/message/764516#764516] Start a new discussion in jBPM at Community [https://community.jboss.org/choose-container!input.jspa?contentType=1&...]