if (networkInterfaces == null) networkInterfaces = getRealNetworkInterfaces ();
Vector networkInterfaces = getRealNetworkInterfaces ();
  public static NetworkInterface getByName (String name)    throws SocketException  {    if (networkInterfaces == null)      networkInterfaces = getRealNetworkInterfaces ();    for (Enumeration e = networkInterfaces.elements ();         e.hasMoreElements (); )      {        NetworkInterface tmp = (NetworkInterface) e.nextElement ();              if (name.equals (tmp.getName ()))          return tmp;      }    throw new SocketException ("no network interface with this name exists");  }