code: public static void checkValidOAuthCallback(String url, String errorMsg) {
  		checkEmptyString(url, errorMsg);
  
  		if (url.toLowerCase().compareToIgnoreCase(OAuthConstants.OUT_OF_BAND) != 0) {
  			check(isUrl(url), errorMsg);
  		}
  	}
docs: Checks that a URL is a valid OAuth callback
  
  @param url      any string
  @param errorMsg error message