I basically agree with David and Alan's comments about this kris with some minor differences:
Blades with 21 luks exist in Java but this particular blade does not match with any standard dapur and is probably not originating from Central Java.
The hilt looks Javanese to me but again not from Central Java as the single patra is not standard. The selut is not original to the hilt IMO.
I would tentatively place the origin of this kris to Java North Coast or East Java
Regards