if someone has put in place the XJ-hydraulic handbrake?
Only Hydraulic Type Hand Brakes I have seen are Cutting (Steering) Brakes.
what components are used in?
Do a Search for Cutting Brake. The Thread I started has info on this. http://www.naxja.org/forum/showthread.php?t=1001264&highlight=cutting+brake
I have an interest in the thing!
Are you talking about a line lock? If so I wouldn't use it for a parking brake as they can bleed down.
The Cherokee doesn't have a stock hydraulic hand brake.