code: static String toHexString(final byte[] b) {
  		StringBuffer sb = new StringBuffer("{");
  		for (int i = 0; i < b.length; i++) {
  			sb.append(toHexString(b[i]));
  			if (i < b.length - 1) {
  				sb.append(",");
  			}
  		}
  		sb.append("}");
  		return sb.toString();
  	}
docs: Converts a byte array into its hexadecimal representation, padding each
  with a leading zero to get an even number of characters.
  
  @param b values to convert
  @return hex string, possibly with elements padded with a zero