Cron Expression

Cron expressions are used to configure instances of CronTrigger class. A Cron expression is a string consisting of six or seven fields separated by white space that represents a set of times, normally as a schedule to execute some routine.

Below list the allowed fields and values.

Name	Mandatory	Constraints	Special Characters
Seconds	Y	0 - 59	, - * /
Minutes	Y	0 - 59	, - * /
Hours	Y	0 - 23	, - * /
Day of month	Y	1 - 31	, - * ? / L W
Month	Y	0 - 11 or JAN - DEC	, - * /
Day of week	Y	1 - 7 or SUN - SAT	, - * ? / L #
Year	N	empty or 1970 - 2099	, - * /

The month and weekday abbreviations are not case-sensitive.

The special characters are used as follow:

Special Character	Description
Asterisk *	Used as wildcard that represents “all”. An asterisk in the hour field is equivalent to every hour.
Comma ,	Used to separate items of a list. E.g., using MON,WED,FRI in the fifth field (day of week) means Mondays, Wednesdays and Fridays.
Dash -	Used to define ranges. E.g., using 2000-2010 indicates every year between 2000 and 2010, inclusive.
Question Mark ?	Used to specify “no specific value”. It is useful when you need to specify something in one of these two fields, but not in the other. For example, a trigger is to fire on the 10th of each month but it does not matter which day of the week, you can use ? in the day-of-week field.
Slash /	Used to skip a given number of values. E.g., */3 in the hour field means 0, 3 ,6, 9, 12, 15, 18, 21. The asterisk * specifies “every hour” but the /3 means only the first, fourth, seventh. etc. You can place a value before the slash to set initial value. E.g., 2/3 means 2, 5, 8, 11, etc.
Hash #	Used in day-of-week field to specify the “nth” xxx day of the month. Must be followed by a number between one and five. E.g., “5#3” in the day of week field corresponds to the third Friday of every month.
Last L	Used in day-of-month and day-of-week fields to specify either the last day of the month or the last xxx day of the month. In day-of-month field, L means the last day of the month, which is day 31 for January or 28 for February (non-leap years). In day-of-week field, L means 7 or SAT. If it is used in the day-of-week field after another value, e.g., 6L means the last Friday of the month.
Weekday W	Used in day-of-month field to specify the weekday of the month nearest to the given day. If 15W is specified in day-of-month field, it means the nearest weekday to the 15th of the month. So, if 15th is s Saturday, the trigger fires on Friday the 14th. If 15th is a Sunday, the trigger fires on Monday the 16th. If 15th is a Tuesday, it fires on Tuesday the 15th. However, if 1W is specified, and 1st is a Saturday, the trigger fires on Monday the 3rd, because it does not “jump” over the boundary of a month’s days.

Some examples of Cron expressions.

Cron Expression	Description
0 0 12 * * ?	Fire at 12:00 pm (noon) every day.
0 15 10 ? * *	Fire at 10:15 am every day.
0 15 10 * * ? 2022	Fire at 10:15 am every day during the year 2022.
0 * 14 * * ?	Fire every minute starting at 2:00 pm and ending at 2:59 pm, every day.
0 0/5 14,18 * * ?	Fire every five minutes starting at 2:00 pm and ending at 2:55 pm, and fire every five minutes starting at 6:00 pm and ending at 6:55 pm, every day.
0 10,44 14 ? 3 WED	Fire 2:10 pm and at 2:44 pm, every Wednesday in the month of March.
0 15 10 ? * 6#3	Fire at 10:15 am on the third Saturday of every month.