Java 计划执行器 : Does it guarantee to not run in parallel if task hast not yet finished

Question

有谁知道 java.util.concurrent 包中的以下 java 方法 ScheduledExecutorService.html#scheduleAtFixedRate()

绝对保证，如果“最后一次”运行的可运行对象尚未完成，则 Runnable 计划永远不会并行运行:

例如(伪代码)

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.

非常感谢简

Answer 1

来自docs :

If any execution of this task takes longer than its period, then subsequent executions may start late, but will not concurrently execute.