code: public static int optInt(JSONObject o, String id, int def) throws JSONConverterException {
          if (o.containsKey(id)) {
              try {
                  return (Integer) o.get(id);
              } catch (ClassCastException e) {
                  throw new JSONConverterException("Unable to read a int from string '" + id + "'", e);
              }
          }
          return def;
      }
docs: Read an optional integer.
  
  @param o  the object to parse
  @param id the key in the map that points to an integer
  @param def the default integer value if the key is absent
  @return the resulting integer
  @throws JSONConverterException if the key does not point to a int