The below code is working in all system Linux (fedora, centos) and windows except one system (linux). 

import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.net.UnknownHostException;

public class Test {

    public static String getMacAddress() {

        try {
            InetAddress address = InetAddress.getLocalHost();

            /*
             * Get NetworkInterface for the current host and then read the
             * hardware address.
             */
            System.out.println(address.getCanonicalHostName());
            System.out.println(address.getHostAddress());
            System.out.println(address.isSiteLocalAddress() );
            NetworkInterface ni = NetworkInterface.getByInetAddress(address);
            System.out.println(ni.getDisplayName());
            System.out.println(ni.isUp());
            byte[] mac = ni.getHardwareAddress();

            /*
             * Extract each array of mac address and convert it to hexa with the
             * following format 00-00-27-AA-4A-9E.
             */
            System.out.println(mac.length); // null pointer exception raising ----------------------------
            StringBuilder macaddress= new StringBuilder();
            for (int i = 0; i < mac.length; i++) {
                macaddress.append(String.format("%02X%s", mac[i], (i < mac.length - 1) ? "-" : "")) ;
            }
            System.out.println("mac "+macaddress);
            return macaddress.toString();
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (SocketException e) {
            e.printStackTrace();
        }
        return "";
    }

public static void main(String args[]){
    Test.getMacAddress();
}

} 

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