code: private static Collection<Location> findMissedClassesDueToLackOfPackageEntry(
              Iterable<URL> classpath, NormalizedResourceName resourceName) {
  
          Set<Location> result = new HashSet<>();
          for (Location location : archiveLocationsOf(classpath)) {
              if (containsEntryWithPrefix(location, resourceName)) {
                  result.add(location.append(resourceName.toString()));
              }
          }
          return result;
      }
docs: Unfortunately the behavior with archives is not completely consistent. Originally,
  {@link Locations#ofPackage(String)} simply asked all {@link java.net.URLClassLoader}s, for
  {@link ClassLoader#getResources(String)} of the respective resource name.
  E.g.
  <pre><code>importPackage("org.junit") -> getResources("/org/junit")</code></pre>
  However, this only works, if all respective archives contain an entry for the folder, which is not always the
  case. Consider the standard JRE "rt.jar", which does not contain an entry "/java/io", but nonetheless
  entries like "/java/io/File.class". Thus an import of "java.io", relying on
  {@link ClassLoader#getResources(String)}, would not import <code>java.io.File</code>.