Many systems use user roles in addition to permissions. A user role is usually a set of permissions; it can be predefined in the system or be user-defined. In BEA AquaLogic Service Registry, the user roles mechanism is implemented by groups. The administrator is allowed to set permissions not only for individual users but also for groups. Instead of restricting the relationship to users and roles, it is possible to create groups, set permissions for them and then add users into these groups. This "group" mechanism in BEA AquaLogic Service Registry is nearly the same as user role mechanism and it is used instead of user roles. For more information, see Group Management.