docs: public static String getHostnameFromFQDN(String fqdn) {
  		if (fqdn == null) {
  			throw new IllegalArgumentException("fqdn is null");
  		}
  		int dotPos = fqdn.indexOf('.');
  		if (dotPos == -1) {
  			return fqdn;
  		} else {
  			return fqdn.substring(0, dotPos);
  		}
  	}