RFR: 8331195: Improve com.sun.net.httpserver.HttpExchange usability [v2]

[Michael McMahon]

> I'd like to return to this issue with a new PR that addresses the usability issue minimally. Namely to define numeric constants
> for the counter-intuitive responseLength values in `HttpExchange.sendResponseHeaders`. The apidoc then refers to the constant names rather than the numeric values.
> 
> I've updated the implementation and some tests (though not all yet) to use the constant names. I'm open to suggestions on the names themselves. Once that is agreed, I'll update the remaining tests and any other call sites in the implementation.
> 
> Thanks,
> Michael

Michael McMahon has updated the pull request incrementally with one additional commit since the last revision:

  doc update

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/28132/files
  - new: https://git.openjdk.org/jdk/pull/28132/files/8fe3a2bd..5f9f259d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28132&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28132&range=00-01

  Stats: 13 lines in 1 file changed: 12 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/28132.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28132/head:pull/28132

PR: https://git.openjdk.org/jdk/pull/28132