RFR JDK-8038310: Re-examine integration of extended Charsets

[Alan Bateman]

On 27/05/2015 20:09, Xueming Shen wrote:
> Hi,
>
> Please help review the change of changing the hard-wired extended 
> charsets loading mechanism
> to ServiceLoader.loadInstalled(), for the module system. With the fix 
> for JDK-8069588 in JDK 9 all
> charsets needed to startup in supported environments are in the base 
> module. This change is to
> use ServiceLoader to load the extended charsets to remove the 
> java.base dependency on jdk.charsets
> moduel.
>
> Issues:
> JDK-8038310: Re-examine integration of extended Charsets
> JDK-8069588: Need to avoid attempting to load extended charsets (from 
> jdk.charsets module) before module system initialization runs
>
> webrev:
> http://cr.openjdk.java.net/~sherman/8069588_8038310/webrev
It's good to get this moved to ServiceLoader as that will make it easy 
for jdk.charsets to be a service provider module.

ExtendedProviderHolder.extendedProviders() returning an array is a 
surprise but okay given that there will mostly be just the one provider. 
Builds for small devices might have zero and would be a bit cleaner to 
return an empty array rather than null. Also a bit cleaner to just use 
the for-each construct, I don't see any reason to use hasNext/next here.

The VM.isBooted check looks right as we should never get here during 
startup if running on a supported configuration.

-Alan