public static int compareKey(byte[] key1, byte[] key2, int length) {
        return Bytes.compareTo(key1, 0, length, key2, 0, length);
    }
public static int compareKey ( byte [ ] key1 , byte [ ] key2 , int length ) { return Bytes . compareTo ( key1 , 0 , length , key2 , 0 , length ) ; }
TODO If the given keys have different length the function will not give the right result.