public static Map<String, String> toMap(JSONObject j) throws JSONException {
    return toMap(j, new HashMap<>(), StringUtils.EMPTY);
  }
Convert Json object to map representation. Nested object are represented by keys like xpath (dot separated)

@param j Json object t convert
@return map representation of json object
@throws JSONException if log can't be parsed into JSON
olv-core/src/main/java/pl/otros/logview/parser/json/JsonExtractor.java