RFR: 8369250: Assess and remedy any unsafe usage of the Semaphore used by NonJavaThread::List

[David Holmes]

On Tue, 7 Oct 2025 08:56:18 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

>> Hmm. This seems to compile on my mac at least:
>> https://github.com/openjdk/jdk/compare/master...stefank:jdk:pull_27664_alternative
>
> http://cppreference.com/w/cpp/language/static.html
>> The declaration inside the class body is not a definition and may declare the member to be of [incomplete type](https://www.cppreference.com/w/cpp/language/incomplete_type.html)

I didn't initially move the definition of the `List` class and it failed to build for me - hence I had to move it.

What is the concern with defining `List` in the header file???

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PR Review Comment: https://git.openjdk.org/jdk/pull/27664#discussion_r2410192880