static String hexToBin(String s) {
        StringBuilder ss = new StringBuilder(new BigInteger(s, 16).toString(2));
        for (int i = ss.length(); i < 4; i++) {
            ss.insert(0, "0");
        }
        return ss.toString();
    }
Why Did you create this class? what does it do?
src/adventofcode/DiskDefragmentation_14.java