JEP 193: Enhanced Volatiles

[David Holmes]

On 6/03/2014 3:22 AM, Remi Forax wrote:
> On 03/05/2014 06:07 PM, Peter Levart wrote:
>>
>> On 03/05/2014 05:55 PM, Jeroen Frijters wrote:
>>> Brian Goetz wrote:
>>>
>>>> I suspect you were expecting this response: we don't add language
>>>> semantics through annotations.
>>> Technically, we're not adding language semantics. The JVM is the one
>>> interpreting the annotations.
>>
>> And the JVM is the one implementing the language semantics (together
>> with javac which feeds the JVM with bytecodes). Language semantcis are
>> implemented by the combination of javac and JVM. If you say that this
>> feature does not require any change to javac, you're just saying that
>> you put all the burden on the JVM, but you *are* implementing the
>> language semantics using annotations nevertheless...
>
> no, it's the other way around. javac maps Java the language to the
> bytecode semantics.
> The JVM only execute bytecodes.

But if the JVM acts upon annotations to change how it executes those 
bytecodes then, as Peter said, the JVM is implementing the language 
semantics.

It is also a bit misleading to say that the JVM only executes bytecodes, 
as the semantics of those bytecodes were driven by the requirements of 
the language. javac + jvm do form a team here.

David

>>
>>
>> Regards, Peter
>
> cheers,
> Rémi
>
>>
>>>> I'm not trying to frustrate you; evolving a language with millions of
>>>> users is really, really hard.  And one of the things that makes it hard
>>>> is recognizing our intrinsic conflicts of interest between "what good
>>>> will this do me" and "what harm will it do others."
>>> I understand, that's why I want to avoid adding language support for
>>> this niche/specialist feature.
>>>
>>> Regards,
>>> Jeroen
>>>
>>
>