A Timed Service (formerly called just service) is a task that is run on a timely basis, performing maintenance tasks like changing active key, or it could generate a report.

A Timed Service framework supports a couple basic properties that is used to calculate when and how a timed service should run. These properties are:

PropertyDescription
ACTIVE "TRUE" if the service should be run, otherwise it is disabled.
SINGLETON "TRUE" if the service only should be run on one of the nodes in the cluster at the time. If it's not set or set to FALSE is the service run simultaneously on all nodes in the cluster. If the node running a singleton service fails will another node sense this and start up the service.
INTERVAL Property defining the interval in seconds the service should run.
INTERVALMS Property defining the interval in milliseconds the service should run. Notice that the platform and application server might put a lower bound on the value. The lower limit for GlassFish is by default 7000 milliseconds but can be changed by editing minimum-delivery-interval-in-millis in domain.xml.
CRON 

Property that should define a CRON expression of how often the service should run. It should conform to Unix CRON standard. (One and only one of INTERVAL, INTERVALMS or CRON is required)

WORK_LOG_TYPES

Property specifying a comma-separated list of log types that should be used for logging invocations of the service.
The following values can be used:

ValueDescription
INFO_LOGGINGUse Log4J info logging
SECURE_AUDITLOGGINGUse CESeCore secure audit logging

By default, if this property is not set, INFO_LOGGING is used. It is possible to turn off logging by setting this property to an empty value. Errors during service invocations will always be logged at error level using Log4J. If the property contains SECURE_AUDITLOGGING, the error will additionally be logged to the audit log.