RFR: 8349206: j.u.l.Handler classes create deadlock risk via synchronized publish() method [v9]

[Daniel Fuchs]

On Thu, 27 Feb 2025 17:15:56 GMT, David Beaumont <duke at openjdk.org> wrote:

>> 8349206: j.u.l.Handler classes create deadlock risk via synchronized publish() method.
>> 
>> 1. Remove synchronization of calls to publish() in Handlers in java.util.logging package.
>> 2. Add explanatory comments to various affected methods.
>> 3. Add a test to ensure deadlocks no longer occur.
>> 
>> Note that this change does not address issue in MemoryHandler (see JDK-8349208).
>
> David Beaumont has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix @implNote to @apiNote.

src/java.logging/share/classes/java/util/logging/StreamHandler.java line 240:

> 238:     void synchronousPostWriteHook() {
> 239:         // Empty by default.
> 240:     }

It would be good to have a comment making it clear that this method is called while holding the monitor on this. I know we have a test for that - but it could be good to make it clear in the code as well.
What about:
Suggestion:

    void synchronousPostWriteHook() {
        // Empty by default. We could do:
        //    assert Thread.holdsLock(this);
        // but this is already covered by unit tests.
    }

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PR Review Comment: https://git.openjdk.org/jdk/pull/23491#discussion_r1975092107