RFR : JDK-8151099 : java.lang.management.ManagementFactory.getPlatformMXBeans() should work even if jdk.management is not present.

[Amit Sapre]

Thanks Alan & Mandy for your review comments.
I will incorporate your comments and send a fresh review.
Amit

-----Original Message-----
From: Mandy Chung 
Sent: Thursday, July 14, 2016 11:32 AM
To: David Holmes
Cc: Amit Sapre; serviceability-dev; Daniel Fuchs
Subject: Re: RFR : JDK-8151099 : java.lang.management.ManagementFactory.getPlatformMXBeans() should work even if jdk.management is not present.


> On Jul 14, 2016, at 8:55 AM, David Holmes <david.holmes at oracle.com> wrote:
> 
> On 13/07/2016 9:06 PM, Mandy Chung wrote:
>> 
>>> On Jul 13, 2016, at 6:56 PM, Amit Sapre <amit.sapre at oracle.com> wrote:
>>> 
>>> Hello,
>>> Please review the fix
>>> 
>>> Bug ID : https://bugs.openjdk.java.net/browse/JDK-8151099
>>> Webrev : http://cr.openjdk.java.net/~hb/sponsorship/8151099/webrev.00/
>> 
>> Looks okay.
>> 
>> You could rename the method to load_and_initialize_klass_or_null to follow the existing naming convention.
> 
> +1 on that "softload" is not suitable.
> 
> My concern is that the code that calls Management::com_sun_management_internal_GarbageCollectorExtImpl_klass
> does not seem to handle getting NULL correctly:
> 
> ./share/vm/services/memoryManager.cpp
> ./share/vm/services/gcNotifier.cpp

Thanks for pointing this out.

We will need to make sure that when jdk.management is present, it will create com.sun.management.internal.GarbageCollectorExtImpl as the GC memory manager objects for jmm_GetMemoryManagers.  That implements com.sun.management.GarbageCollectorMXBean.

When jdk.management is not present, it should return sun.management.GarbageCollectorImpl instead that implements java.lang.management.GarbageCollectorMXBean.

gcNotifier implements both com.sun.management.GcInfo as well as java.lang.management.MemoryPoolMXBean notification.  More surgery might need to be done to make sure the implementation handles properly when jdk.management is present and absent.

Mandy