Retrieving Network Interfaces in java

/*
 * This example is from javareference.com
 * for more information visit,
 * https://www.javareference.com
 */

import java.net.*;
import java.util.*;

/**
 * This class displays the list of all available network interfaces
 * and sub interfaces on a machine.
 *
 * @author Rahul Sapkal(rahul@javareference.com)
 */
public class NetworkInterfacesRetriever {
  /**
   * Constructor
   */
  public NetworkInterfacesRetriever() {
    try {
      displayInterfaces();
    }
    catch (SocketException se) {
      System.out.println("Socket Exception: " + se.getMessage());
    }
  }

  /**
   * This method prints the machine information and
   * list all the network interfaces with sub interfaces
   * of each network interface if they exists
   *
   * @throws SocketException
   */
  private void displayInterfaces() throws SocketException {
    //Get the Network interfaces using the NetworkInterface class
    try {
      Enumeration<NetworkInterface> ifEnum = NetworkInterface.getNetworkInterfaces();

      InetAddress machine = InetAddress.getLocalHost();
      System.out.println("\nMachine Information");
      System.out.println("------------------------------------------");
      System.out.println("\tMachine Name: " + machine.getHostName());
      System.out.println("\tMachine IP Address: " + machine.getHostAddress());
      System.out.println("------------------------------------------\n\n");

      if (ifEnum != null) {
        System.out.println("Network Interfaces");
        System.out.println("------------------------------------------\n");

        //display the enum
        for (NetworkInterface netIf : Collections.list(ifEnum)) {
          System.out.println("Display Name: " + netIf.getDisplayName());
          System.out.println("Interface Name: " + netIf.getName());

          //get the addresses of this interface
          Enumeration<InetAddress> ifAddrEnum = netIf.getInetAddresses();
          System.out.print("Addresses: ");

          for (InetAddress ifAddr : Collections.list(ifAddrEnum)) {
            System.out.print(ifAddr.toString() + "  ");
          }

          displaySubInterfaces(netIf);

          System.out.println("\n---------------------------------------\n");
        }
      } else {
        //if the enumeration is null, mean no network interfaces were found
        System.out.println("No network interfaces were found");
      }
    } catch (Exception e) {
      System.out.println("Error: " + e);
    }
  }

  /**
   * This method takes a network interface as a paramter
   * and prints its sub interfaces if they exists
   *
   * @param netIf
   * @throws SocketException
   */
  private void displaySubInterfaces(NetworkInterface netIf) throws SocketException {
    Enumeration<NetworkInterface> subNetIfs = netIf.getSubInterfaces();

    for (NetworkInterface subNetIf : Collections.list(subNetIfs)) {
      System.out.println("\n\t-------------------------------");
      System.out.println("\tSub Interface Display name: " + subNetIf.getDisplayName());
      System.out.println("\tSub Interface Name: " + subNetIf.getName());
    }
  }

  /**
   * Main method to run as an Application
   *
   * @param args
   */
  public static void main(String[] args) {
    NetworkInterfacesRetriever netIf = new NetworkInterfacesRetriever();
  }
}