Incompatible change to java.lang.instrument.Instrumentation

[Sven Reimers]

Hi Peter,

nice idea. The only drawback is this requires JDK 9 for a build. What I
wanted to check is if I can compile the same unchanged source tree with JDK
8 and 9...

Since there is not yet a hard requirement for JDK 9 compilation, i.e. this
is just an experiment to figure out things that may be broken and need
work, I would not see any actions on NetBeans side at the moment. I was
just astonished about the breaking change naively assuming that default
methods should be an easy fix.

Thanks for the hint, waiting what Alan comes up with in the meantime
(probably more projects could be hit by the problem)

@Alan: Shall I file a bug?

Thanks for the fast responses

Sven

On Fri, Jun 16, 2017 at 10:21 AM, Peter Levart <peter.levart at gmail.com>
wrote:

> Hi Sven,
>
> Just an idea...
>
> What NetBeans could probably do is to create a special sub-interface of
> java.lang.instrument.Instrumentation in its bootstrap jar file (the jar
> passed to class-path) and make that jar file MR jar with two versions of
> say org.netbeans.core.Instrumentation interfaces extending
> java.lang.instrument.Instrumentation. The one for pre-9 JDK would have an
> empty body while the one for JDK 9 would override the newly introduced
> abstract methods with default implementations. NetBeans implementation
> classes would then implement org.netbeans.core.Instrumentation instead of
> java.lang.instrument.Instrumentation.
>
> Regards, Peter
>
>
> On 06/16/2017 09:40 AM, Jaroslav Tulach wrote:
>
>> On pátek 16. června 2017 8:17:51 CEST Sven Reimers wrote:
>>
>>> Hi Alan,
>>>
>>> the code in question I am looking at is in
>>>
>>>   o.n.bootstrap/src/org/netbeans/NbInstrumentation.java
>>>
>>> So this looks more like some basic stuff baked deep into NetBeans core...
>>>
>>> cc'Ing Jaroslav Tulach who wrote this - he should have some more
>>> details..
>>> else I will try to figure this out.
>>>
>>> Thanks for looking into this
>>>
>>> Sven
>>>
>>>
>>> On Fri, Jun 16, 2017 at 8:11 AM, Alan Bateman <Alan.Bateman at oracle.com>
>>>
>>> wrote:
>>>
>>>> On 16/06/2017 06:54, Sven Reimers wrote:
>>>>
>>>>> Hi all,
>>>>>
>>>>> as part of the process of the code donation from Oracle to Apache for
>>>>> NetBeans I tried a compilation of the source code using idk 9-ea+173.
>>>>> The
>>>>> compilation fails due to an added method boolean
>>>>> isModifiableModule(Module)
>>>>> in java.lang.instrument.Instrumentation.
>>>>>
>>>>> Should the newly added method on the interface Instrumentation have a
>>>>> default implementation to make this change source code compatible from
>>>>> 8
>>>>> to
>>>>> 9, e.g.
>>>>>
>>>>> default boolean isModifiableModule(Module module) {
>>>>>
>>>>>       return false;
>>>>>
>>>>> }
>>>>>
>>>>>
>>>>> Is it already to late for changing this before JDK 9 release?
>>>>>
>>>>> You are correct that adding abstract methods to Instrumentation is an
>>>>>
>>>> incompatible change but the long term assumption in this area has always
>>>> been it wouldn't be implemented outside of the java.instrument module.
>>>> There were 4 abstract methods added to it in Java SE 6 and I don't
>>>> recall
>>>> anyone screaming (pre-dates default methods of course).
>>>>
>>> Looks like I have implemented the code when compiling against JDK7.
>>
>> So can you say what NetBeans is doing? Is this mocking, maybe
>>>> forwarding/intercepting?
>>>>
>>> See https://netbeans.org/bugzilla/show_bug.cgi?id=237919
>>
>> If there is a compelling reasons then we could
>>>> try
>>>> to see about changing redefineModule and the other new methods to be
>>>> default methods but it is late and there is more to this that changing
>>>> them
>>>> to be default methods.
>>>>
>>> -jt
>>
>>
>


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