Java Scheduled Executor：如果任务尚未完成，它是否保证不并行运行

Question

有没有人知道java.util.concurrent包中的以下java方法 ScheduledExecutorService.html＃scheduleAtFixedRate（）

绝对保证，如果来自“最后”的可运行的话，Runnable预定将永远不会并行运行。跑还没完呢：

例如（Pseudocode）

1.00 o'clock: scheduleAtFixedRate(MyRunnable, "Run ever Hour")`
//1.30 o'clock: MyRunnable Has finished (everthing is fine)
2.00 o'clock: MyRunnable is triggered to run again
3.00 o'clock: MyRunnable has NOT yet finished ==> What will happen here? 
Will java Simply SKIP the starting of MyRunnable (as the old instance has not yet 
finished) and try again at 4 o'clock or will Java start a NEW MyRunnable that then will 
run in parallel to the "old" MyRunnable.

非常感谢你 Jan

Answer 1

来自 docs ：

  

如果执行此任务，则执行此操作   那么比它的时期更长   随后的处决可能会迟到，   但不会同时执行。