JDK-8301180: Replace NULL with nullptr in share/gc/parallel/

[jdksjolen]

Hi, this PR changes all occurrences of NULL to nullptr for the subdirectory share/gc/parallel/. Unfortunately the script that does the change isn't perfect, and so we
need to comb through these manually to make sure nothing has gone wrong. I also review these changes but things slip past my eyes sometimes.

Here are some typical things to look out for:

1. No changes but copyright header changed (probably because I reverted some changes but forgot the copyright).
2. Macros having their NULL changed to nullptr, these are added to the script when I find them. They should be NULL.
3. nullptr in comments and logs. We try to use lower case "null" in these cases as it reads better. An exception is made when code expressions are in a comment.

An example of this:

// This function returns null
void* ret_null();
// This function returns true if *x == nullptr
bool is_nullptr(void** x);

Note how nullptr participates in a code expression here, we really are talking about the specific value nullptr.

Thanks!

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8301180: Replace NULL with nullptr in share/gc/parallel/

Reviewers

• Stefan Karlsson (@stefank - Reviewer) ⚠️ Review applies to 018199d5
• Albert Mingkun Yang (@albertnetymk - Reviewer)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk pull/12227/head:pull/12227
$ git checkout pull/12227

Update a local copy of the PR:
$ git checkout pull/12227
$ git pull https://git.openjdk.org/jdk pull/12227/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 12227

View PR using the GUI difftool:
$ git pr show -t 12227

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/12227.diff

[bridgekeeper]

👋 Welcome back jsjolen! 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]

@jdksjolen this pull request can not be integrated into master due to one or more merge conflicts. To resolve these merge conflicts and update this pull request you can run the following commands in the local repository for your personal fork:

git checkout JDK-8301180
git fetch https://git.openjdk.org/jdk master
git merge FETCH_HEAD
# resolve conflicts and follow the instructions given by git merge
git commit -m "Merge master"
git push

[openjdk]

@jdksjolen The following label will be automatically applied to this pull request:

• hotspot-gc

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

[mlbridge]

Webrevs

• 01: Full (cddf5912)
• 00: Full (018199d5)

[openjdk]

@jdksjolen 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:

8301180: Replace NULL with nullptr in share/gc/parallel/

Reviewed-by: stefank, ayang

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 no new commits pushed to the master branch. If another commit should be pushed before you perform the /integrate command, your PR will be automatically rebased. If you prefer to avoid any potential 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.

[jdksjolen]

/integrate

Thanks

[openjdk]

Going to push as commit 3758487.
Since your change was applied there has been 1 commit pushed to the master branch:

• d7aa87f: 8300176: URLEncoder/URLDecoder static fields should be private static final

Your commit was automatically rebased without conflicts.

[openjdk]

@jdksjolen Pushed as commit 3758487.

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