8369921: [lworld] Remove caches of primitive wrapper classes

[RogerRiggs]

Disable use of wrapper cached values when --enable-preview and add javadoc descriptions for enable-preview.
The wrapper classes are Byte, Short, Character, Integer, and Long.

---

Progress

• Change must not contain extraneous whitespace

Issue

• JDK-8369921: [lworld] Remove caches of primitive wrapper classes (Bug - P4)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/valhalla.git pull/1685/head:pull/1685
$ git checkout pull/1685

Update a local copy of the PR:
$ git checkout pull/1685
$ git pull https://git.openjdk.org/valhalla.git pull/1685/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 1685

View PR using the GUI difftool:
$ git pr show -t 1685

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/valhalla/pull/1685.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back rriggs! A progress list of the required criteria for merging this PR into lworld will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@RogerRiggs This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8369921: [lworld] Remove caches of primitive wrapper classes

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 1 new commit pushed to the lworld branch:

• cccb501: 8367073: [lworld] Conform to JEP 450 encoding of mark word

Please see this link for an up-to-date comparison between the source branch of this pull request and the lworld branch.
As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the lworld branch, type /integrate in a new comment.

[mlbridge]

Webrevs

• 00: Full (5b7e32a8)

[jddarcy]

No tests need to be updated; java/lang/Integer/ValueOf.java passes with this change?

[RogerRiggs]

No tests need to be updated; java/lang/Integer/ValueOf.java passes with this change?

The tests use == (acmp) to compare. In Valhalla acmp for value classes does a field by field (recursive) comparison.
It is not possible to detect a difference between any two value class instances (assuming their fields have the same values) regardless of their source.

[liach]

I recommend moving this into the preview feature block too.

[liach]

Same remark, I recommend moving this into the preview feature check block.

[liach]

Double and Float already do new, so they are fine. Should we update Boolean.valueOf to return new Boolean instead of TRUE or FALSE?