static boolean isIn8Days(int d, String f, Date date) {
        return false;
    }

    static boolean isBetween8And14Days(int d, String f, Date date) {
        return false;
    }

    static class Pair<K, V> {
        public Pair(K first, V second) {
            this.first = first;
            this.second = second;
        }

        K first;
        V second;
    }

    static <V> V test(Pair<Supplier<Boolean>, V>... suppliers) {
        for (Pair<Supplier<Boolean>, V> supplier : suppliers) {
            if (supplier.first.get()) {
                return supplier.second;
            }
        }
        return null;
    }

    public static void main(String[] args) {
        int d = 1;
        String firstSearch = "a";
        Date date = new Date();
        int B = 20, C = 20;

        test(new Pair<>(() -> isIn8Days(d, firstSearch, date), B),
                new Pair<>(() -> isBetween8And14Days(d, firstSearch, date), C)
        );
        
    }