RFR: 8350753: Deprecate UseCompressedClassPointers [v4]

[Coleen Phillimore]

On Mon, 7 Apr 2025 10:02:19 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> Deprecates UseCompressedClassPointers. For the lengthy description of why and how we do this, please read the lengthy [CSR](https://bugs.openjdk.org/browse/JDK-8350754).
>> 
>> Testing:
>> 
>> I ran all jtreg tests manually on Linux-x64 that used the flag in some form (55 tests) to ensure they don't trip over the added deprecation output.
>> 
>> I also tested the JVM on arm32 to verify that UseCompressedClassPointers had never been available there, and that we don't start printing a confusing deprecation message now.
>
> Thomas Stuefe has updated the pull request incrementally with one additional commit since the last revision:
> 
>   move line

test/hotspot/jtreg/runtime/CommandLine/VMDeprecatedOptions.java line 62:

> 60:             {"AllowRedefinitionToAddDeleteMethods", "true"},
> 61:             {"LockingMode", "1"},
> 62:             {"UseCompressedClassPointers", "false"},

If  you run this test on an arm32, will it fail because UseCompressedClassPointers is unrecognized there?  Does this need to be conditional on 64 bit platforms?

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PR Review Comment: https://git.openjdk.org/jdk/pull/24436#discussion_r2031115368