Spring cron expression for every after 30 minutes

According to the Quartz-Scheduler Tutorial
It should be value="0 0/30 * * * ?"

The field order of the cronExpression is

1. Seconds
2. Minutes
3. Hours
4. Day-of-Month
5. Month
6. Day-of-Week
7. Year (optional field)

Ensure you have at least 6 parameters or you will get an error (year is optional).