protected final String[] parseKey(String key) {
        Matcher m = KEY_PATTERN.matcher(key);

        if (m.find()) {
            return new String[] {cleanKey(m.group()), key.substring(m.end())};
        } else {
            return null; // NOSONAR
        }
    }
loads keys

@param key   the key
@param value the values
src/main/java/spark/QueryParamsMap.java