I need a cron-expression (0 0/60 * * * ?) to fire application every 12 hours (twice a day).
Use e.g. 0 0 3,15 * * ?
That'll run a job at 3am and 3pm. That's twice a day, with 12 hours between.
You could use 0 0 0/12 * * ?
which means every 12 hours. Here's some examples.