Example code in JDK8 requiring change for modular function

[Alan Bateman]

On 06/05/2012 13:36, David Holmes wrote:
> :
>>
>> When running in "modular mode" the system class loader is the class 
>> loader of the entry module, where as what we really want to use is 
>> the class loader of the callee (the class loader used to load Files).
>
>
> The system class loader needed not be the classloader of the callee. 
> So if we expect this to use the loader of the callee then the code is 
> broken regardless of module-mode.
This code works as specified, if you have a custom file type detector 
then you put it on the system class path and it will be located.

To work with modules it requires changes, including specification 
changes. This goes for many other areas of the JDK, I assume Paul just 
picked this one out to start a discussion on the changes that will need 
to happen across the board. In this case the specification will need to 
make it clear how it works when running with modules. 
Implementation-wise it will require the base module to have "requires 
optional service java.nio.file.spi.FileTypeDetector" in its module 
declaration and the ServiceLoader usage changed as the legacy system 
class loader notion doesn't make sense when running with modules. For 
this case then loadInstalled is fine. It would also be fine to use 
Files.class.getClassLoader, assuming that it returns a ModuleClassLoader 
(that's a TBD for the base module in Mandy's slides).

-Alan.