private static File getOriginalFile(ProtectionDomain protectionDomain) {
        // CodeSource is null for dynamically defined classes, or if the ClassLoader doesn't set them properly.
        CodeSource cs = protectionDomain.getCodeSource();
        URL originalUrl = cs != null ? cs.getLocation() : null;
        if (originalUrl == null || !"file".equals(originalUrl.getProtocol())) {
            // Cannot transform classes from anything but files