RFR: 8251989: Hex formatting and parsing utility

[Roger Riggs]

On Fri, 2 Oct 2020 15:18:04 GMT, Roger Riggs <rriggs at openjdk.org> wrote:

> java.util.HexFormat utility:
> 
>  - Format and parse hexadecimal strings, with parameters for delimiter, prefix, suffix and upper/lowercase
>  - Static factories and builder methods to create HexFormat copies with modified parameters.
>  - Consistent naming of methods for conversion of byte arrays to formatted strings and back: formatHex and parseHex
>  - Consistent naming of methods for conversion of primitive types: toHexDigits... and fromHexDigits...
>  - Prefix and suffixes now apply to each formatted value, not the string as a whole
>  - Using java.util.Appendable as a target for buffered conversions so output to Writers and PrintStreams
>    like System.out are supported in addition to StringBuilder. (IOExceptions are converted to unchecked exceptions)
>  - Immutable and thread safe, a "value-based" class
> 
> See the [HexFormat
> javadoc](http://cr.openjdk.java.net/~rriggs/8251989-hex-formatter/java.base/java/util/HexFormat.html) for details.
> Review comments and suggestions welcome.

To avoid spamming email lists, I'm removing the i18n, net, nio, and security labels since most developers already are
subscribed to core-libs. Please re-add a label if you think it is useful to the email list.

-------------

PR: https://git.openjdk.java.net/jdk/pull/482