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Null-Pointer Exception in ProcessInstanceResource.java

Question asked by hheg8837 on Jul 20, 2012
Latest reply on Jul 23, 2012 by frederikheremans1
Hi all,

I tried to enable the history-feature for variables with  <property name="history" value="full" /> in activiti-context.xml in order to see variable updates via the rest method "ProcessInstance/{processId}".

My process contains null-values by default because some variables are set in later tasks.

No, I wanted to test the feature and figured out that this is a problem:

private void addVariableList(String processInstanceId, ObjectNode responseJSON) {
    List<HistoricDetail> variableList = ActivitiUtil.getHistoryService()
        .createHistoricDetailQuery()
        .processInstanceId(processInstanceId)
        .variableUpdates()
        .orderByTime()
        .desc()
        .list();
   
    if(variableList != null && variableList.size() > 0) {
      ArrayNode variablesJSON = new ObjectMapper().createArrayNode();
      responseJSON.put("variables", variablesJSON);
      for (HistoricDetail historicDetail : variableList) {
        HistoricVariableUpdate variableUpdate = (HistoricVariableUpdate) historicDetail;
        ObjectNode variableJSON = new ObjectMapper().createObjectNode();
        variableJSON.put("variableName", variableUpdate.getVariableName());
        variableJSON.put("variableValue", variableUpdate.getValue().toString());
        variableJSON.put("variableType", variableUpdate.getVariableTypeName());
        variableJSON.put("revision", variableUpdate.getRevision());
        variableJSON.put("time", RequestUtil.dateToString(variableUpdate.getTime()));
       
        variablesJSON.add(variableJSON);
      }
    }
  }

The exception happens at

variableJSON.put("variableValue", variableUpdate.getValue().toString());

java.lang.NullPointerException
        at org.activiti.rest.api.process.ProcessInstanceResource.addVariableList(ProcessInstanceResource.java:163)

because some of my variables are null.

I think it can be a normal condition that variables are null, so I think this is a bug.

Is there a bug-tracker where I can report this problem or is it sufficient to post it here in the forum?

All the best,
Thomas

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