On Mon, 4 Jul 2022 12:09:46 GMT, David Holmes <[email protected]> wrote:
>>> Is "deadlock" accurate?
>>
>> Yes.
>>
>> In the context of the specification, "shutdown hook" means _application_
>> shutdown hook - as far as the specification is concerned, application
>> shutdown hooks are the only kind of hooks. Right?
>>
>> For example, the following will deadlock (when run with the changes in this
>> PR):
>>
>>
>> public class TestHook {
>> public static void main(String... arg) {
>> Thread hook = new Thread("my-hook") {
>> @Override
>> public void run() {
>> System.exit(1);
>> }
>> };
>> Runtime.getRuntime().addShutdownHook(hook);
>> System.exit(0);
>> }
>> }
>
> It is a general deadlock, not a monitor based deadlock: the thread that
> called exit and holds the lock has to join() the hook thread. The hook thread
> blocks on the lock held by the exiting thread. Neither thread can progress.
You folks are correct. I hadn't noticed the ApplicationShutdownHooks thing.
Sorry for the noise.
-------------
PR: https://git.openjdk.org/jdk/pull/9351
