Job Scheduler service is widely used in eXo products. Here are some examples of Jobs:
Automatically send notification, such as task/event reminder in the Calendar application.
Automatically save chat messages from Openfire Server to History in the Chat application.
Deactivate topics in the Forum application.
Calculate the number of active and online users in the Forum application.
Automatically collect RSS items from various RSS resources to post to the activity stream of users and spaces in eXo Social.
Automatically send Newsletters to users in WCM.
By using Job Scheduler service in eXo kernel, many kinds of Job can be configured to run, such as addPeriodJob, addCronJob, addGlobalJobListener, addJobListener and many more. Just write a Job (a class implements Job interface of quartz library) and configure plug-in for JobSchedulerService and it is done.