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

[Amit Sapre]

Hello,

I have incorporate review comments and updated changes are available in this webrev:
Updated Webrev : http://cr.openjdk.java.net/~asapre/webrev/8151099/webrev.01/ 

Couple of existing tests have been updated to test these changes

Tests under jdk directory :-
 
java/lang/management/MemoryPoolMXBean
java/lang/management/GarbageCollectorMXBean
java/lang/management/ManagementFactory

Were manually re-run using -limit-modules=java.management. These tests passed.

Thanks,
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
>