public static boolean isJarURL(URL url) {
        String up = url.getProtocol();
        return (URL_PROTOCOL_JAR.equals(up) || URL_PROTOCOL_ZIP.equals(up) || URL_PROTOCOL_WSJAR.equals(up));
    }
Determine whether the given URL points to a resource in a jar file,
that is, has protocol "jar", "zip", "wsjar" or "code-source".
<p>"zip" and "wsjar" are used by WebLogic Server and WebSphere, respectively,
but can be treated like jar files.

@param url the URL to check
@return whether the URL has been identified as a JAR URL
src/main/java/spark/utils/ResourceUtils.java