The JMS client can optionally control this transaction explicitly, such as to coordinate receiving a message from one queue with sending a message on another queue in the same messaging system.
The first line will pop up a message on the control nodes' display (if X Window System is active), letting the user know that the laptop is inactive and needs to be powered down.
第一行将在控制节点的界面上弹出消息（如果 X Window System 处于活动状态），从而让用户知道笔记本处于非活动状态并且需要关闭。