code: protected void initQueue(T queue, QueueSpec spec) throws Exception {
          queue.setObserver(defaultObserver);
          queue.init();
      }
docs: Initializes a newly created queue instance.
  
  <p>
  Called by {@link #createAndInitQueue(QueueSpec)}. Sub-class may override
  this method to implement its own business logic.
  </p>
  
  @param queue
  @param spec