public class MacAddressTest
{
  public static void main(String[] args) throws Exception
  {
    Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces();

    while (interfaces.hasMoreElements())
    {
      NetworkInterface nif = interfaces.nextElement();
      byte[] lBytes = nif.getHardwareAddress();
      StringBuffer lStringBuffer = new StringBuffer();

      if (lBytes != null)
      {
        for (byte b : lBytes)
        {
          lStringBuffer.append(String.format("%1$02X ", new Byte(b)));
        }
      }

      System.out.println(lStringBuffer);
    }
  }
}