RFR 8251989: Hex encoder and decoder utility

[Chris Hegarty]

> On 19 Aug 2020, at 22:14, Roger Riggs <Roger.Riggs at oracle.com> wrote:
> 
> ..
> JavaDoc:
> http://cr.openjdk.java.net/~rriggs/hex-javadoc/java.base/java/util/Hex.html

I like it Roger, very nice. A few minor comments/quibbles:

Hex:

- "Utilities to encode bytes to hex strings and decode hex strings to bytes.” - This class consists solely of “factory methods" for creating encoders and decoders to ..

- In the example, do you want to assert that the byte arrays `bytes` and `dec` are equal?

- RFC 4752 or RFC 2752. Which one is it? ;-)

Decoder:

- decode​(char[] chars, int index, int length) - " A valid character array consists only of the delimiters, prefix, suffix, and an even number of hex digits.” - its just the portion of the array that is required to consist of …, right. You need to add “range”, or similar.

Please use “ReturnS” consistently ( I see a few Return (no S) ). Actually, there are a few others, e.g. “Convert”. Can you take pass over all these, in all three classes? 

-Chris.