code: private JsonToken readingConstant(JsonTokenType type, JsonToken token) {
          try {
              int numCharsToRead = ((String) type.getValidator()).length();
              char[] chars = new char[numCharsToRead];
              reader.read(chars);
              String stringRead = new String(chars);
  
              if (stringRead.equals(type.getValidator())) {
                  token.setEndColumn(token.getStartColumn() + numCharsToRead);
                  token.setText(stringRead);
                  return token;
              } else {
                  throwJsonException(stringRead, type);
              }
          } catch (IOException ioe) {
              throw new JsonException("An IO exception occurred while reading the JSON payload", ioe);
          }
          return null;
      }
docs: When a constant token type is expected, check that the expected constant is read,
  and update the content of the token accordingly.
  
  @param type the token type
  @param token the token
  @return the token updated with end column and text updated