Well, this is not an OSGi question (OSGi does not cover event planning like crontab), I would say that using a third-party open source scheduler such as Quartz:
http://quartz-scheduler.org/
However, this is not an OSGi kit out of the box, so it may still take some effort to get it working.
: Apache Sling, , ( Quartz), Sling OSGi, .
http://sling.apache.org/documentation/bundles/scheduler-service-commons-scheduler.html
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