RFR: JDK-8187498: Add a -Xmanagement flag as syntactic sugar for -Dcom.sun.management.jmxremote.* properties

[Harsha Wardhana B]

On Wednesday 21 February 2018 01:51 AM, mandy chung wrote:
> The code review and CSR review can be in parallel.  For this case,
> I agree with Kumar to have CSR written that would help the code
> review. Please specify the behavior and its relationship with
> jcmd and other relevant diagnosability tools.
ok.
>
> On 2/20/18 6:41 AM, Kumar Srinivasan wrote:
>>
>>>>> What is the behavior when -Dcom.sun.management.jmxremote.port=1234 
>>>>> --start-management-agent port=2345 
>>>>> -Dcom.sun.management.jmxremote.port=3456?
>>>>>
>>>>> What is the value of the system property 
>>>>> com.sun.management.jmxremote.port at runtime?  What port number 
>>>>> does the management server start with?
>>>> As said earlier, values set via new flags override values set by -D 
>>>> flags. So 2345 will be the value of 
>>>> com.sun.management.jmxremote.port. Added a test case to validate that.
>
> VM options are the last one wins if same option specified multiple 
> times.  In this case, it could cause confusion (the last -D option 
> sets the value to 3456 but it's set to a different value).
>
> Why not taking the simplest approach - when --start-management-agent 
> is set, it does not accept mixing the old way (i.e. does not accept 
> the management properties to be set via -D)?   This RFE is to make the 
> command-line simpler and ease-of-use.  I don't see any downside to 
> migrate entirely to the new form.
We cannot get rid of specifying options via -D. We have plenty of -D 
flags but very few have short-hand alternative via 
--start-management-agent. If management properties are specified by 
--start-management-agent, the options specified by -D are anyway 
overwritten if specified.
>
> Mandy
Harsha