I know this question was asked before. But the answers in those questions are not correct in my opinion.
I want to have a CronExpression for (Quartz) that schedules every 2 days.
The CronExpression "should be" 0 0 0 1/2 * ? *.
BUT: Starting today (9th October 2017) CronMaker shows that this is not true. This expression basically means: schedule every 2 days starting on the first of each month. That means: starting on 9th October 2017 the next times are:
Wednesday, October 11, 2017 12:00 AM
Friday, October 13, 2017 12:00 AM
Sunday, October 15, 2017 12:00 AM
Tuesday, October 17, 2017 12:00 AM
Thursday, October 19, 2017 12:00 AM
Saturday, October 21, 2017 12:00 AM
Monday, October 23, 2017 12:00 AM
Wednesday, October 25, 2017 12:00 AM
Friday, October 27, 2017 12:00 AM
Sunday, October 29, 2017 12:00 AM
Tuesday, October 31, 2017 12:00 AM
Wednesday, November 1, 2017 12:00 AM
As you can see: There is only 1 day between the two last times.
So when I'm using freeformatter to describe the cronexpression it states:
At 00:00:00am, every 2 days starting on the 1st, every month
Well that is shown in the listed times above. But I need something that correctly fires every 2 days.
Tuesday, October 31, 2017 12:00 AM
Thursday, November 2, 2017 12:00 AM
and so on.
Apparently the simple trigger from quartz is not a real option for me!
It's becouse you misunderstood how cron expression works. For every month it will starts from first day of month. If it would work otherly, the next month wouldn't fit 1/2 part of expression.
For more detailed explanation, look here: