Should ClassLoader::getResouces return the same resource twice?

[Thiago Henrique Hupner]

I guess a little context can make more things clear:
The servlet spec requires that all jars from WEB-INF/lib
be available to the same classloader.
The resource, in particular, is "META-INF/web-fragment.xml"
Each jar can contain its own. So, using getResources make sense
in order of parsing each. However, what is happening is if I have two JARs
each with its own META-INF/web-fragment.xml, using the ModuleReader
it is returning four resources, so it parses more than it should and it
fails
to parse the same resource twice.

I'll have a try only exposing the ".class" files in the ModuleReader,
so the Loader will be able to create the classes and it will read the
resources
from the classloader.

I'm using my own implementations of the ModuleReader, ModuleFinder
and ModuleDescriptor because all of our resources are in memory I wasn't
able to
use the ModuleFinder.of() because it requires a filesystem.

Em sáb., 2 de jan. de 2021 às 04:07, Alan Bateman <Alan.Bateman at oracle.com>
escreveu:

> On 02/01/2021 03:21, Thiago Henrique Hupner wrote:
> > :
> >
> > I've created a simple example of what is occurring [1].
> > I know there are behavior specific for getting a class if it is in a
> module,
> > but I don't know if this may be a bug in the resource loading mechanism.
> > In the example, the returned values are different to illustrate, but in
> my
> > case, it
> > returns two exact URLs for the same resource as the source for the module
> > reader
> > and the classloader is the same.
> The behavior you observe with the example is correct.
> ClassLoader.getResources locates the resource by searching the lass
> loader delegation chain and in the example there are two "foo"
> resources. The resource in module fake.module is located because it is
> an automatic module that opens all its packages unconditionally. The
> second resource is located by searching the parent class loader, a
> URLClassLoader in the example that also locates "foo".  Which "foo" did
> you expect to locate? If code in fake.module just wants to locate the
> resource in its own module then it should use getResource rather than
> getResources.
>
> -Alan.
>