FF4J is a proposition of Feature Toggle pattern. The purpose is to be able to enable and disable features at runtime with dedicated consoles. FF4J let you choose among a list of technologies to persist the state of your features: xml, jdbc, mongodb, redis, neo4j, any JSR107 cache ...
Features are just a special type of property (boolean) so we implement all sutff for you to define, update and inject Property at runtime using the same stores technologies and the same screens.