code: public synchronized Map<String, List<Integer>> getList() {
      final Map<String, List<Integer>> tasks = new LinkedHashMap<>();
  
      tasks.put("Running", getTaskIdList(runningTasks));
      tasks.put("Waiting", getTaskIdList(taskQueue));
      tasks.put("Finished", getTaskIdList(finishedTasks));
      tasks.put("Canceled", getTaskIdList(canceledTasks));
  
      return tasks;
    }
docs: Get the list of Tasks, which are grouped by the states.
  @return a Map grouped by task state, each with a List of taskIds.