jmx-dev RFR: 8010285 Enforce the requirement of Management Interfaces being public

[Jaroslav Bachorik]

On Wed 29 May 2013 07:44:34 PM CEST, Daniel Fuchs wrote:
> On 5/29/13 7:17 PM, Jaroslav Bachorik wrote:
>> On Wed 29 May 2013 05:33:21 PM CEST, Eamonn McManus wrote:
>>> I would recommend against changing the code to do additional calls to
>>> Class.forName during MBean introspection. As I recall we made the
>>> opposite change some years ago, both because Class.forName can be slow
>>> (it may call out to a user ClassLoader) and because it is a potential
>>> source of security problems.
>>
>> Thanks. I was trying to dig some history from mercurial but couldn't.
>> Walking through all the related interfaces is equally acceptable - I've
>> tried both of the solutions and they test well with the regtests.
>>
>> I am still puzzled by the current implementation which will fail to
>> locate the correct MBean interface in eg.
>>
>> <<CInterface>> extends <<BInterface>> extends <<ServiceMBean>>
>>
>> ClassA extends Service implements <<CInterface>>
>>
>> as the process would stop on <<BInterface>> (checks the superclass of
>> the ClassA, checks all the interfaces implemented by the Service class,
>> checks all the interfaces extended by <<CInterface>>) which plainly
>> does not conform to the MBean interface naming convention and would
>> miss the <<ServiceMBean>> interface.
>
> Hi Jaroslav,
>
> <<Service>> would have to implement <<ServiceMBean>> either
> directly or indirectly.
>
> So the current implementation is correct.
>
> If <<ServiceMBean>> is not assignable from <<Service>> then
> <<ServiceMBean>> is not an MBean interface for ClassA.

Actually, when you do
ClassA extends Service implements <<BInterface>>

the Introspector will return <<ServiceMBean>> as the standard mbean 
interface for ClassA. I've just tried it on a simple project to make 
sure I understand the code correctly. The puzzle is which behaviour is 
correct? Either all the levels of the interface hierarchy should be 
checked for the [className]MBean interfaces or none, I guess. However, 
I can not find anything in the spec related to this case.

-JB-

>
> You can work around that by wrapping an instance of ClassA
> in an instance of  javax.management.StandardMBean, and by
> specifying <<ServiceMBean>>.class as the MBean interface
> in the constructor.
>
> Hope this helps,
>
> -- daniel
>
>>
>> -JB-
>>
>>>
>>> Éamonn
>>>
>>>
>>> 2013/5/29 Jaroslav Bachorik <jaroslav.bachorik at oracle.com
>>> <mailto:jaroslav.bachorik at oracle.com>>
>>>
>>>      Updated webrev -
>>>      http://cr.openjdk.java.net/~jbachorik/8010285/webrev.01
>>>
>>>      It adds regtests and takes care of the comments from David and
>>>      Shanliang.
>>>
>>>      -JB-
>>>
>>>      On 05/28/2013 04:22 PM, Jaroslav Bachorik wrote:
>>>      > The fix enforces the management interfaces (read MBean and
>>> MXBean
>>>      > interfaces) being public. While this is defined in the
>>>      specification it
>>>      > was not enforced in any way and it was allowed to create MBeans
>>>      for eg.
>>>      > private MBean interfaces.
>>>      >
>>>      > The fix adds checks when creating and registering MBeans and
>>> throws
>>>      > javax.management.NotCompliantMBeanException when a user tries to
>>>      create
>>>      > an MBean with non-public management interface.
>>>      >
>>>      > Since this change can cause problems for users having non-public
>>>      > management interfaces a system property is introduced that will
>>>      revert
>>>      > to the old behaviour when set
>>> (com.sun.jmx.mbeans.allowNonPublic).
>>>      >
>>>      > Thanks,
>>>      >
>>>      > -JB-
>>>      >
>>>
>>>
>>
>>
>