private static String getEffectiveAttribute(
            final Attributes mainAttributes,
            final Optional<Attributes> perEntryAttributes,
            final Attributes.Name attributeName) {
        final String mainAttribute = mainAttributes.getValue(attributeName);
        return (String) perEntryAttributes.orElse(mainAttributes).getOrDefault(attributeName, mainAttribute);
    }
Finds resources recognized as the given name.

<p>Note that {@link java.net.URLClassLoader#findResources} is public while {@link java.lang.ClassLoader#findResources}
is protected.
embulk-core/src/main/java/org/embulk/cli/SelfContainedJarAwareURLClassLoader.java