public static String getIPAddress(boolean useIPv4) {
        try {
            List<NetworkInterface> interfaces = Collections.list(NetworkInterface.getNetworkInterfaces());
            for (NetworkInterface intf : interfaces) {
                List<InetAddress> addrs = Collections.list(intf.getInetAddresses());
                for (InetAddress addr : addrs) {
                    if (!addr.isLoopbackAddress()) {
                        String sAddr = addr.getHostAddress().toUpperCase();
                        boolean isIPv4 = InetAddressUtils.isIPv4Address(sAddr); 
                        if (useIPv4) {
                            if (isIPv4) 
                                return sAddr;
                        } else {
                            if (!isIPv4) {
                                int delim = sAddr.indexOf('%'); // drop ip6 port suffix
                                return delim<0 ? sAddr : sAddr.substring(0, delim);
                            }
                        }
                    }
                }
            }
        } catch (Exception ex) { } // for now eat exceptions
        return "";
    }