if(req.length() < 1) {
throw new IllegalArgumentException(
"Blank submissions from the client are invalid.");
}
Zipcode zipcode = ZipcodeManager.getZipcode(req);
String state = zipcode.getState();
String city = zipcode.getCity();
if((state==null || state.length()<1) || (city==null || city.length()<1))
return null;
String jsonString = "{\"state\":\""+state+"\", \"city\":\""+city+"\"}";
return jsonString;
