The Application Server allows to trigger the execution of stored job definitions immediately. I.e. a job is triggered based on a stored job definition. Only the owner of the store job definition or users with the system permission Manage stored jobs definitions (22) can  execute stored job definitions immediately. The job triggered will impersonate as the owner of the stored job definition.

Note that immediate execution means that the a job based on this stored job definition is immediately put on the job queue, i.e. it is up to the job engine when the job is then really executed.