How to validate CronSequenceGenerator cron expressions?

Question

How could I validate cron expressions that are prepared for use of CronSequenceGenerator?

I mean, I cannot wait until the cron executes automatically as I'm defining like monthly intervals.

Is the following correct? How can I be sure?

monthly at midnight: `0 0 0 1 * *`
monthly at 1 am: `0 0 1 1 * *`
weekly, on sunday at midnight: `0 0 0 * * SUN`

Answer 1

The Spring's CronSequenceGenerator class has a method isValidExpression(String expression) which takes the cron expression and returns a boolean.

Answer 2

I guess if you are ok with quartz api then you should use org.quartz.CronExpression.isValidExpression(String s)

Api ref http://quartz-scheduler.org/api/2.2.0/org/quartz/CronExpression.html