RFR: 8338139: {ClassLoading, Memory}MXBean::isVerbose methods are inconsistent with their setVerbose methods

[Stefan Karlsson]

On Mon, 19 Aug 2024 16:26:02 GMT, Leonid Mesnik <lmesnik at openjdk.org> wrote:

>> The `ClassLoadingMXBean` and `MemoryMXBean` APIs have `setVerbose` methods to control verbose mode and `isVerbose` methods to query it. Some JCK tests expect `setVerbose(false)` to disable verbose mode and, subsequently, `isVerbose()` to return false. However, if logging to a file is enabled by using -Xlog on the java launcher command line then `isVerbose()` returns true even after calling `setVerbose(false)`.
>> 
>> The proposed patch solves this by introducing two changes:
>> 
>> 1) The previous implementation used the `log_is_enabled` functionality to check if logging was enabled for the given tag set. This returns true if logging has been turned on for *any* output. The patch changes this so that `isVerbose` only checks what has been configured for stdout, which is the output that `setVerbose` configures.
>> 
>> 2) The previous implementation of `setVerbose` turned on `class+load*` (notice the star) but then `isVerbose` only checked `class+load` (without the star). The patch changes this so that the `isVerbose` in-effect checks `class+load*`. (The `gc` part of the patch did not have this problem)
>> 
>> The main focus on this patch is to fix the JCK failure, with an implementation that follows the API documentation. While looking at this area of the code it is clear that there are other problems that we might want to addressed in the future, but we're intentionally keeping this patch limited in scope so that it can be backported to JDK 23.
>> 
>> A CSR for this change has been created.
>> 
>> Testing:
>> * The newly implemented tests
>> * The failing JCK tests with the corresponding -Xlog lines
>> * Tier1-7 (running)
>> 
>> The patch is co-authored by me and David Holmes
>
> test/jdk/java/lang/management/MemoryMXBean/TestVerboseMemory.java line 30:
> 
>> 28:  *          related unified logging is enabled.
>> 29:  *
>> 30:  * @run main/othervm -Xlog:gc=trace:file=vm.log TestVerboseMemory false
> 
> Does it makes sense to add case where not only 'gc' logging is set from CLI with file output? It would be the exact copy of failed case. 
> 
> @run main/othervm -Xlog:all=trace:file=vm.log TestVerboseMemory false
> 
> (Same for ClassLoading Bean)

Yes, that's a good suggestion. I've updated the tests.

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PR Review Comment: https://git.openjdk.org/jdk/pull/20628#discussion_r1722264852