Depends on your question actually.
If you're talking about Jazz Bass sounding ala Fender Jazz Bass, then yes pickups have to be swapped. If yours is already a Jazz bass copy or a bass with Jazz bass pickups, then all you have to do is search for Tesla/DiMarzio/EMG/Seymour Duncan/Bartolini/Aguilar/MEC jazz pickups that you like. If yours is a bass with 2 soapbar pickups ala Spector, then the only choice you have are the EMG 35/40/45-Js, which are essentially jazz pickups in soapbar housings, with
- 35 for 4 string
- 40 for 5 string
- 45 for 6 string
However, if you're talking about modifying your bass to sound jazz-y as in the genre, then it's more than just pickups. Strings play a part too - half-rounds, flats, etc. However, if you have an active bass that has an internal preamp, it's easy to emulate a jazz tone via tone knobs. Maybe you just need to change the pickups to jazz-y sounding pickups, then further enhance the tone with the internal preamp, plus your choice of strings.