code: public static String toHexString(long hash) {
          String hex = Long.toHexString(hash);
  
          if (hex.length() == 16) {
              return hex;
          }
  
          StringBuilder sb = new StringBuilder();
          for (int i = 0, j = 16 - hex.length(); i < j; i++) {
              sb.append('0');
          }
  
          return sb.append(hex).toString();
      }
docs: Converts a hash to a hexidecimal representation.
  
  @param hash
  the finalized hash value to convert to hex.
  @return
  a {@link String} representation of the hash.