JEP-238 & JEP-261 Coexistence

[Richard Opalka]

Clarification below:

On 04/06/2016 01:47 PM, Richard Opalka wrote:
> Comments below:
>
> On 04/06/2016 12:34 PM, Alan Bateman wrote:
>> On 06/04/2016 11:17, Richard Opalka wrote:
>>> Hi Experts,
>>>
>>>    I expected if users provide 'multirelease' jar file with 
>>> modules-info.class
>>> placed in its META-INF/versions/9 folder would work without problems.
>>> But I'm getting:
>>>
>>> Caused by: java.lang.IllegalArgumentException: META-INF.versions.9: 
>>> Invalid package name:  Illegal character at index 4
>>>
>>> instead. Does it mean JEP-238 and JEP-261 cannot coexist?
>> There isn't any support yet for modular JAR as multi-release JARs. 
>> It's tracked as JDK-8146486 with the main question being whether the 
>> compiled module declaration can be in the META-INF/versions tree or not.
>>
>> As things stand then a JAR file that does not have a 
>> module-info.class in the top level directory is assumed to be an 
>> automatic module so this is why it barps when trying to determine a 
>> package name from META-INF/versions/9.
> IMHO it should be allowed to put module-info.class to META-INF/versions
> subtree as modules may evolve (their imports/exports) with different 
> JDK versions. // My 2c.
'requires' module section may change with different JDKs if new useful 
API is introduced in JDK
and it is used by the multirelease module (I mean change not affecting 
the multirelease jar exposed API)
>>
>> BTW: Just looking at the contents of your JAR file then it looks like 
>> this is the EE version of the Common Annotations. In that case you 
>> shouldn't need a multi-release JAR. Instead you should be able to put 
>> the module-info.class in the top level directory and deploy it on the 
>> upgrade module path.
> Yes I know. Our requirement is to support both JDK8 and JDK9 with the 
> same jar.
> Thus in my experiments I have javax classes compiled for JDK8 and 
> module-info.class for JDK9.
> Multi-Release jar was my first attempt, when it failed I did what you 
> propose above Alan.
>>
>> -Alan
> Rio
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