public @interface Scheduled

Runs this method of a bean on a schedule.

Exactly one of cron, fixedRate or fixedDelay (or their String forms) must be given. The method takes no arguments.

A literal cron expression is parsed by the build, which writes its fields into the entry point as bit masks and refuses a malformed one: an expression nobody noticed was wrong otherwise fires never, or every second. One that reads configuration (${report.cron}) is parsed once at start-up instead.

The format is Spring’s six fields – second, minute, hour, day of month, month, day of week – plus the @yearly, @monthly, @weekly, @daily and @hourly macros:

@Scheduled(cron = "0 */15 * * * MON-FRI")
public void refresh() { ... }

Several instances of one server each run every job. lock makes a job run on one of them at a time, through a row in the database.