RFR: 8371748: Remove the (empty) ThreadPoolExecutor.finalize() method

[ExE Boss]

On Thu, 13 Nov 2025 23:10:59 GMT, Brent Christian <bchristi at openjdk.org> wrote:

> From the bug report:
> Prior to JDK 11, ThreadPoolExecutor.finalize() was specified to
> "[invoke] shutdown() when this executor is no longer referenced and it has no threads."
> 
> In JDK 11, ThreadPoolExecutor.finalize() was re-specified to do nothing, leaving the finalize() method empty. ([JDK-8190324](https://bugs.openjdk.org/browse/JDK-8190324)).
> 
> In JDK 18, finalize() was deprecated for removal ([JDK-8276447](https://bugs.openjdk.org/browse/JDK-8276447)), after first being "standard" deprecated in JDK 9 ([JDK-8165641](https://bugs.openjdk.org/browse/JDK-8165641)).
> 
> The finalize() method can safely be removed from ThreadPoolExecutor.

Wrt. the **CSR**’s “**Compatibility Risk Description**”:
> Subclasses that @⁠Override finalize, call super.finalize() or call finalize() directly will continue to compile and execute.

This isn’t completely correct, as `super.finalize()` will now have `throws Throwable`, where it previously didn’t, causing a source incompatibility, as seen in `ThreadPoolExecutorSubclassTest`:
> ```
> /home/runner/work/jdk/jdk/test/jdk/java/util/concurrent/tck/ThreadPoolExecutorSubclassTest.java:2011:
> error: unreported exception Throwable; must be caught or declared to be thrown
>                 super.finalize();
>                               ^
> ```

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PR Comment: https://git.openjdk.org/jdk/pull/28311#issuecomment-3540202811