精确的毫秒计数器，用定时计算，音视频同步分析，-Ms accurate counters, used from time to time, the analysis of audio and video synchronization, etc.

java时钟，有监听事件，时间计数器，每一秒触发一次，绘制图形-java clock, there are monitor events, time counter, every second the trigger once, drawing graphics