Java – * and *? In spring @ scheduled (cron = “…”)

I've been looking at the spring boot example to schedule tasks（ https://spring.io/guides/gs/scheduling-tasks/ ）And read some documents（ https://javahunter.wordpress.com/2011/05/05/cronscheduler-in-spring/ ）, I see * and? Almost interchangeable

For example, row

@Scheduled(cron = "0 15 10 ? * *")

and

@Scheduled(cron = "0 15 10 * * ?")

Do the same thing So * and? What's the difference?

Solution

Asterix represents all possible values Question marks apply to non-specific values

Copy from tutorial