code: public String getCountryByLatLon(double lat, double lon){
  		double[] q = new double[2];
  		q[0] = lat;
  		q[1] = lon;
  		LightweightGeoObject city = null;
  		try {
  			city = (LightweightGeoObject)tree.nearest(q);
  		} catch (KeySizeException e) {
  			logger.error(e.getMessage());
  		}
  		if (city == null) return null;
  		return countryCodes.get(city.getCountryCode());
  	}
docs: Given a pair of lat/lon coordinates return the country where it belongs.
  @param lat
  @param lon
  @return Name of country where it belongs.