code: public Object parse(Reader reader) {
          if (reader == null) {
              throw new IllegalArgumentException("Reader must not be null");
          }
  
          Object content;
          JsonParser parser = createParser();
          content = parser.parse(reader);
          return content;
      }
docs: Parse a JSON data structure from content from a reader
  
  @param reader reader over a JSON content
  @return a data structure of lists and maps