code: @Override
    public String dnsResolve(String host) {
      try {
        return InetAddress.getByName(host).getHostAddress();
      } catch (UnknownHostException e) {
        log.log(Level.FINE, "DNS name not resolvable {0}.", host);
      }
      return "";
    }
docs: ***********************************************************************
  Resolves the given DNS host name into an IP address, and returns it in the
  dot separated format as a string.
  
  @param host
  the host to resolve.
  @return the resolved IP, empty string if not resolvable.
  **********************************************************************