code: private static void listHierarchy(Task task, String indent)
     {
        for (Task child : task.getChildTasks())
        {
           System.out.println(indent + "Task: " + child.getName() + "\t" + child.getStart() + "\t" + child.getFinish());
           listHierarchy(child, indent + " ");
        }
     }
docs: Helper method called recursively to list child tasks.
  
  @param task task whose children are to be displayed
  @param indent whitespace used to indent hierarchy levels