When the subsystem receives a work request, the system searches the classification rules for a matching qualifier and its service class or report class. Because a piece of work can have more than one work qualifier associated with it, it may match more than one classification rule. Therefore, the order in which you specify the classification rules determines which service classes are assigned.
Prior to z/OS® V1R3, with the IEAICSxx, the system used a set order for searching the work qualifiers. With workload management, there is no set order. You define it. Only the subsystem type must be the first level qualifier for classification rules. You determine the rest of search order by the order in which you specify the classification rules. You can use a different hierarchy for each subsystem.
Suppose you are defining your JES classification rules. For all work requests coming into the JES2 subsystem instance, you want to assign work with user ID MNGRBIG and jobname PERFEVAL to service class BATSLOW. All other work with user ID beginning with MNGR should be assigned to service class BATHOT. So in this case, the hierarchy for the JES subsystem is: