Java scheduled executor

A typical usage of java scheduled executor looks like this

ScheduledExecutorService executor = Executors.newScheduledThreadPool(1);
 executor.scheduleWithFixedDelay(() -> System.out.println("Hello"), 0, 1, TimeUnit.SECONDS);

However, we shall be careful of the pitfall marked below. When there exists potential failing codes, it’s better to try catch the block so that the job can keep running without unexpected termination.

对于Java的定时任务类ScheduledExecutorService，如果提交的周期任务可能出错，建议加上try catch以防止后续任务不再执行。

/**
 * Creates and executes a periodic action that becomes enabled first
 * after the given initial delay, and subsequently with the
 * given delay between the termination of one execution and the
 * commencement of the next.  If any execution of the task
 * encounters an exception, subsequent executions are suppressed.
 * Otherwise, the task will only terminate via cancellation or
 * termination of the executor.
 *
 * @param command the task to execute
 * @param initialDelay the time to delay first execution
 * @param delay the delay between the termination of one
 * execution and the commencement of the next
 * @param unit the time unit of the initialDelay and delay parameters
 * @return a ScheduledFuture representing pending completion of
 *         the task, and whose {@code get()} method will throw an
 *         exception upon cancellation
 * @throws RejectedExecutionException if the task cannot be
 *         scheduled for execution
 * @throws NullPointerException if command is null
 * @throws IllegalArgumentException if delay less than or equal to zero
 */
public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command,
                                                 long initialDelay,
                                                 long delay,
                                                 TimeUnit unit);