title: How to validate CronSequenceGenerator cron expressions?
body: <p>How could I validate <code>cron</code> expressions that are prepared for use of <code>CronSequenceGenerator</code>?</p>
  
  <p>I mean, I cannot wait until the cron executes automatically as I'm defining like monthly intervals.</p>
  
  <p>Is the following correct? How can I be sure?</p>
  
  <pre><code>monthly at midnight: `0 0 0 1 * *`
  monthly at 1 am: `0 0 1 1 * *`
  weekly, on sunday at midnight: `0 0 0 * * SUN`
  </code></pre>