Proper way to scan all classes inside application/war files

[Sundara Mohan M]

Thank you Alan


On Fri, Apr 19, 2019 at 12:48 AM Alan Bateman <Alan.Bateman at oracle.com>
wrote:

> On 19/04/2019 01:33, Sundara Mohan M wrote:
> > Hi,
> >     I was scanning all classes (to find all annotated class) using the
> > URLClassLoader.getUrls() methods to find all URL and find it with JDK8.
> > Since JDK9 onwards all App/System Class loaders are not deriving from
> > URLClassLoader it doesn't work anymore. (solution of making ucp variable
> > inside BuiltinClassLoader accesible and reading URLs works).
> I think you are looking for the "java.class.path" system property. Split
> the value, map each element to a file path and file URL, and you should
> the equivalent to the array of URLs that getURLs would have given you.
> Same limitations too in that it's just the initial class path and
> doesn't taken into account additions that arise when JAR files have the
> Class-Path attribute.
>
> >
> > What is the proper way to scan all(AppClassLoader + any other class
> loader)
> > classes?
> >
> This is a bigger question. I suspect you are looking to enumerate all
> the resources in all modules in the boot layer. The following will print
> the names of all resources in all modules in the boot layer and might
> give you ideas:
>
>       ModuleLayer.boot().configuration().modules().forEach(m -> {
>              System.out.format("module %s%n", m.name());
>              try (ModuleReader reader = m.reference().open()) {
>                  reader.list().forEach(rn -> System.out.format("
> %s%n", rn));
>              } catch (IOException ioe) {
>                  throw new UncheckedIOException(ioe);
>              }
>          });
>
> In addition you want the resources on the class path and I think you
> have code for this already once you map the value of java.class.path to
> a sequence of file URLs.
>
> -Alan
>