8071507: (ref) Clear phantom reference as soft and weak references do

[poonamparhar]

These changes backport the following fixes to jdk8u-ri:

• 8071507: (ref) Clear phantom reference as soft and weak references do
• 8143847: Remove REF_CLEANER reference category

With these changes, phantom references are automatically cleared by the garbage collector as soft and weak references.

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• Change must be properly reviewed

Issues

• JDK-8071507: (ref) Clear phantom reference as soft and weak references do ⚠️ Issue is not open.
• JDK-8143847: Remove REF_CLEANER reference category ⚠️ Issue is not open.

Reviewers

• Mandy Chung (@mlchung - Reviewer) ⚠️ Review applies to 8bee95e
• Kim Barrett (@kimbarrett - no project role) ⚠️ Review applies to 8bee95e
• Iris Clark (@irisclark - Author)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/jdk8u-ri pull/4/head:pull/4
$ git checkout pull/4

Update a local copy of the PR:
$ git checkout pull/4
$ git pull https://git.openjdk.java.net/jdk8u-ri pull/4/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 4

View PR using the GUI difftool:
$ git pr show -t 4

Using diff file

Download this PR as a diff file:
https://git.openjdk.java.net/jdk8u-ri/pull/4.diff

[poonamparhar]

/issue add JDK-8143847

[bridgekeeper]

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

[openjdk]

@poonamparhar The issue 8071931 was not found in the JDK project - make sure you have entered it correctly.
As there were validation problems, no additional issues will be added to the list of solved issues.

[openjdk]

@poonamparhar
Adding additional issue to issue list: 8143847: Remove REF_CLEANER reference category.

[mlbridge]

Webrevs

• 01: Full - Incremental (35aa32d0)
• 00: Full (8bee95e2)

[mlchung]

/csr

[openjdk]

@mlchung has indicated that a compatibility and specification (CSR) request is needed for this pull request.
@poonamparhar please create a CSR request for issue JDK-8071507. This pull request cannot be integrated until the CSR request is approved.

[mlchung]

The change looks good to me.

[kimbarrett]

Looks good.

[openjdk]

@poonamparhar
Adding additional issue to issue list: 8285096: (ref) Clear phantom reference as soft and weak references do.

[poonamparhar]

/issue remove JDK-8285096

[openjdk]

@poonamparhar
Removing additional issue from issue list: 8285096.

[irisclark]

Is the word "scheduling" repeated at both the end of unchanged line 48 and the beginning of new line 49?

[mlchung]

Good catch! Both Kim and I missed this.

[poonamparhar]

Thanks Iris. Removed the duplicate "scheduling".

[irisclark]

Update spec looks good.

[poonamparhar]

/issue add JDK-8285096

[openjdk]

@poonamparhar
Adding additional issue to issue list: 8285096: (ref) Clear phantom reference as soft and weak references do.

[mlchung]

/csr unneeded

[openjdk]

@mlchung determined that a CSR request is not needed for this pull request.

[poonamparhar]

/issue remove JDK-8285096

[openjdk]

@poonamparhar
Removing additional issue from issue list: 8285096.

[openjdk]

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

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

8071507: (ref) Clear phantom reference as soft and weak references do
8143847: Remove REF_CLEANER reference category

Reviewed-by: mchung, kbarrett, iris

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 master branch:

• d63ed0a: 8284907: Compact profiles build fails with GNU make 4

Please see this link for an up-to-date comparison between the source branch of this pull request and the master 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 master branch, type /integrate in a new comment.

[mlchung]

JDK-8285096 is the CSR. Looks like it was not recognized that blocked the integration. Taking /csr out seems to help.

[poonamparhar]

/integrate

[openjdk]

Going to push as commit ad6cdea.
Since your change was applied there has been 1 commit pushed to the master branch:

• d63ed0a: 8284907: Compact profiles build fails with GNU make 4

Your commit was automatically rebased without conflicts.

[openjdk]

@poonamparhar Pushed as commit ad6cdea.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

[gnu-andrew]

Is there a reason for backporting two changes in one PR? I see this was done in 8u42 as well. It makes it harder to review than necessary, notably where the two change the same code in referenceProcessor.cpp.

Also, SKARA does not appear to be picking this up as a backport, as the "Backport " style was not used (https://wiki.openjdk.org/display/SKARA/Backports). Ideally it would refer to the changeset in 8u42, ad6cdea5ae385623afa86251a8278c9c5274f4c1, but it may have to be one of the three original changesets from jdk

In the code itself, three files are missing copyright header changes where they are newer than the current version: referenceProcessor.hpp, referenceProcessor.cpp" and referenceType.hpp`. 8143847 bumps all of these to 2016 and this change should do the same. The other files already have a newer copyright year than in 8143847.