RFR: 8297295: Remove ThreadGroup.allowThreadSuspension [v3]

[Joe Darcy]

On Thu, 8 Dec 2022 17:15:46 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>> Another small step in the multi-release/multi-year effort to remove cruft from Thread/ThreadGroup.
>> 
>> java.lang.ThreadGroup.allowThreadSuspension(boolean) dates from JDK 1.1 and the Classic VM. The method controlled whether threads were suspended when the GC failed. It appears to have interacted with a callback mechanism that could potentially free memory, allowing the GC to retry. The method was never specified .
>> 
>> The method was deprecated and changed to do nothing in JDK 1.2. It was deprecated for removal in Java 14. 
>> 
>> A corpus analysis of 30M classes in 130k artifacts found 0 usages of this method.
>> 
>> It is time to finally remove this method. The compatibility impact should be negligible. Joe, Stuart and I discussed briefly and think early in JDK 21 is a good time to do this.
>
> Alan Bateman has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
> 
>  - Merge
>  - Merge
>  - Remove allowThreadSuspension

Still looks good.

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PR: https://git.openjdk.org/jdk/pull/11373