how to get machines mac address
<p>I want get machines' MAC address..but below written code only display the MAC address when Internet is connected to my machine other it will return null... I am using windows 7</p>

<pre><code>import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.net.UnknownHostException;

class test
{
    public static void main(String[] args)
    {
        InetAddress ip;
        try {
            ip = InetAddress.getLocalHost();

            System.out.println("The mac Address of this machine is :" + ip.getHostAddress());

            NetworkInterface network = NetworkInterface.getByInetAddress(ip);

            byte[] mac = network.getHardwareAddress();

            System.out.print("The mac address is : ");

            StringBuilder sb = new StringBuilder();
            for (int i = 0; i &lt; mac.length; i++){
                sb.append(String.format("%02X%s", mac[i],(i&lt; mac.length - 1)?"-":""));
            }

            System.out.println(sb.toString());

        } 
        catch (UnknownHostException e) {
            e.printStackTrace();
        } 
        catch (SocketException e) {
            e.printStackTrace();
        }
    }
}
</code></pre>
