Factions is a plugin made for Spigot used by the J76-Factions server. It adds factions, pvp wrappers to prevent players from logging out while in combat, an economy system and much more. To use it, you will need SQLite as a library (put inside plugins/libs/ folder) and Spigot or Bukkit version 1.13.2+.
This is a Maven project. You will need a maven environment to compile this project successfully, as well as an Internet connection to download the required libraries. Once you have compiled it, you can find the compiled .jar inside target/, which you can then copy into plugins/ on your server directory. The plugin will automatically setup the database for you the first time.