@Configuration //This piece of shit will tell spring boot that this is a configuration class
public class FF4jConfig {
    //Feature Name Definition
    public static final String PAPA_FEATURE = "PAPA_FEATURE";

    /*
    * FF4J Configuration
    * Create one bean of type FF4J. Why? Because concept of overriding is dying
    * Create of instance of FF4j. Obviously to use it further
    * Register your Feature
    * Enable or disable according to you
    * You are done, Thank me later (Code Below ⬇️)_
    */
    @Bean
    public FF4j ff4j(){
        FF4j ff4j = new FF4j();
        Feature papaFeature = new Feature(PAPA_FEATURE);
        papaFeature.disable(); //Default we will disable this feature later we will be enable
        ff4j.createFeature(papaFeature);
        return ff4j;
    }
}

    @GetMapping(path = "/should-we-party")
    public String shouldWeParty(){
        if(ff4j.check(FF4jConfig.PAPA_FEATURE))
            return "Yeah Johny Lets Go for party";
        else
            return "Sorry Johny, Papa is at Home";
    }

    /*
     * End-point will change the status of the feature
     * In our case it will notify johny about status of papa
     */
    @PostMapping(path = "/papa-at-hospital/{isAtHospital}")
    public String papaAtHospital(@PathVariable boolean isAtHospital){
        if(isAtHospital){
            ff4j.enable(FF4jConfig.PAPA_FEATURE);
            return ("Message deliverd to danny: PAPA IS AT HOSPITAL, GO PARTY");
        }
        else {
            ff4j.disable(FF4jConfig.PAPA_FEATURE);
            return ("Message deliverd to danny: PAPA LEFT HOSPITAL, COME BACK");
        }
    }

@Autowired
    FF4j ff4j;