code: public static ImmutableSet<File> findJarFiles(ClassLoader first, ClassLoader... rest)
        throws IOException {
      Scanner scanner = new Scanner();
      Map<URI, ClassLoader> map = Maps.newLinkedHashMap();
      for (ClassLoader classLoader : Lists.asList(first, rest)) {
        map.putAll(getClassPathEntries(classLoader));
      }
      for (Map.Entry<URI, ClassLoader> entry : map.entrySet()) {
        scanner.scan(entry.getKey(), entry.getValue());
      }
      return scanner.jarFiles();
    }
docs: Returns a list of jar files reachable from the given class loaders.
  
  <p>Currently only {@link URLClassLoader} and only {@code file://} urls are supported.
  
  @throws IOException if the attempt to read class path resources (jar files or directories)
  failed.