On Aug 30, 2012, at 8:59 AM, Joe Wang <[email protected]> wrote:
> Alan, Paul,
>
> While I was writing a summery as you suggested below, I noticed an issue with
> using ServiceLoader. I was trying to use the word 'delegate' but found the
> ServiceLoader might be doing sth. different than the original jaxp process.
>
> Here's the spec:
> The ServiceLoader.load(service) is equivalent to ServiceLoader.load(service,
> Thread.currentThread().getContextClassLoader()) where "loader - The class
> loader to be used to load provider-configuration files and provider classes,
> or null if the system class loader (or, failing that, the bootstrap class
> loader) is to be used "
>
>
> Somehow, our earlier discussion concluded that the original process I
> created, where the context class loader is tried first, if no provider found,
> bootstrap classloader will be tried next, could be 'delegated' to the
> ServiceLoader. But the above didn't really showed that. When I looked at the
> code, it actually simply returns false if loader.getResources fails to find a
> provider.
The CL.getResources will also delegate to the parent CL if one is present which
should eventually get to the bootstrap CL.
> Also, it calls ClassLoader.getSystemResources when loader=null. The later
> would be a regression to CR6723276 if we had called
> ServiceLoader.load(service, loader) with loader=null.
>
Seems as OK as i said in the previous email, since
Object.class.getResourceAsStream does:
public InputStream getResourceAsStream(String name) {
name = resolveName(name);
ClassLoader cl = getClassLoader0(); // <--- This will be null for
Object.class
if (cl==null) {
// A system class.
return ClassLoader.getSystemResourceAsStream(name); // <--- Look!
}
return cl.getResourceAsStream(name);
}
This area is complicated i think you need to write some SL tests.
Paul.
