JES2 has the flexibility to fulfill an installation's unique processing needs. An installation can virtually control every JES2 function. You can perform many customization tasks when JES2 is installed, and you can dynamically customize JES2 whenever your processing needs change. JES2 provides initialization statements, commands, IBM-supplied exit points, the ability to add installation-defined exit points that require minimal source code modification, and the ability to change many commands and system messages, all without the need to modify the IBM-supplied code. See Customizing your JES2 system for a more complete description of these customization facilities.