Any time that you perform factory setups, install language packs, change the database, or change property files, you should create or rebuild the resource jar.
Answer:
Any time that you perform factory setups, install language packs, change the database, or change property files, you should create or rebuild the resource jar. You can do this once after you have completed all factory setups for all add-ons, or you can rebuild the resource jar after performing factory setup for each add-on.