In Quartz cron expressions, ? means “no specific value” in the day-of-month or day-of-week field; L means a last calendar day or weekday, depending on its position; W selects the weekday nearest a day of the month; and # selects the nth occurrence of a weekday in a month. These symbols have Quartz-specific meanings, so check your scheduler’s documentation before applying them elsewhere.
Where these symbols appear in a Quartz expression
Quartz expressions have separate day-of-month and day-of-week fields. The special symbols discussed here act in those fields, and their meaning depends on which field contains them. The official Quartz 2.5.1 CronExpression API documents the parser’s syntax; the Quartz 2.3.0 CronTrigger tutorial gives additional examples.
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What does ? mean?
? means “no specific value.” Quartz allows it in either the day-of-month or day-of-week field. It is typically used in the field that you are not using to choose a day. Quartz documentation says support for specifying both a day-of-month and a day-of-week value is incomplete, so ordinarily put the specific day selection in one field and ? in the other.
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What does L mean?
L means a “last” value, but the result depends on the day field and its position.
- Day-of-month:
Lmeans the last calendar day of the month. - Day-of-week by itself:
Lmeans 7, or Saturday. - Day-of-week after a weekday value: A value followed by
Lmeans that weekday’s last occurrence in the month. For example,6LorFRILmeans the last Friday, using Quartz’s example numbering. LWin day-of-month: This means the last weekday of the month.
Avoid combining L with lists or ranges: Quartz warns that these combinations can produce confusing or unexpected results.
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What does W mean?
W selects the weekday (Monday through Friday) nearest a specified day-of-month number. For example, 15W selects the 15th if it is a weekday, the 14th if the 15th is a Saturday, or the 16th if the 15th is a Sunday. It will not move into a different month: if the first is a Saturday, 1W resolves to Monday the 3rd.
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What does # mean?
# selects the nth occurrence of a weekday in the month, in the day-of-week field. In Quartz’s numbering examples, 6#3 is the third Friday, 2#1 is the first Monday, and 4#5 is the fifth Wednesday. If the requested occurrence does not exist in a particular month, the trigger does not fire that month.
A day-of-week field using # can contain only one expression. For example, Quartz documents 3#1,6#3 as invalid. The expression 0 0 9 ? * 2#1 means 09:00 on the first Monday of each month.
How to read the examples safely
These expressions illustrate the special-character rules, not every scheduling setting. In particular, the examples do not specify an application’s time zone or other trigger configuration. Validate an expression against the Quartz version used by your application before deploying it; the official API documents CronExpression as a parser and evaluator.
Cron syntax differs among schedulers. The definitions here follow the Quartz 2.5.1 API and Quartz 2.3.0 tutorial; a different scheduler, or a different Quartz release, may require checking its own documentation for compatibility and edge cases.
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