title: Spring batch Cron expression: to run every 3 hours
body: <p>I want my spring batch job to run every 3 hours</p>
  
  <p>I used expression <code>* * */3 * * ?</code> this starts the job at the hour that is divisible by 3 e.g. say the server was started at 2 PM the job starts executing only at 3 PM - so far so good but the job keeps starting every second! Is it because I used * in the 1st position?</p>
  
  <p>I tried <code>0 0 */3 * * ?</code> but it is erroring out. What is the best way to achieve this?</p>