public synchronized List<TaskDisplay> getTaskDisplays() {
    List<TaskDisplay> taskDisplays = new ArrayList<TaskDisplay>();
    taskDisplays.addAll(tasks.values());
    return taskDisplays;
  }
Preferred objectMapper for this class.

It must be used to have things work in shaded environment (and its also more performant).
ql/src/java/org/apache/hadoop/hive/ql/QueryDisplay.java