Get MAC Address of System in Java [duplicate]

Question

I need to get the mac address of the system running the program. But I am not able to do that.

I am writing following code:

public class App{

       public static void main(String[] args){

        InetAddress ip;
        try {

            ip = InetAddress.getLocalHost();
            System.out.println("Current IP address : " + ip.getHostAddress());

            NetworkInterface network = NetworkInterface.getByInetAddress(ip);

            byte[] mac = network.getHardwareAddress();

            System.out.print("Current MAC address : ");

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

        } catch (UnknownHostException e) {

            e.printStackTrace();

        } catch (SocketException e){

            e.printStackTrace();

        }

       }

    }

And I am getting following results:

 Current IP address : 14.96.192.202
 Current MAC address : 

I am not getting the MAC Address it is blank.

I saw this example from here

Answer 1

If you account for multiple interfaces, and some null MAC addresses (I'm running Java 7 on Windows 7 with VMWare installed (so I have some virtual network adapters)) then this code seems to work:

public static void main(String[] args) {
  try {
    InetAddress ip = InetAddress.getLocalHost();
    System.out.println("Current IP address : " + ip.getHostAddress());

    Enumeration<NetworkInterface> networks = NetworkInterface.getNetworkInterfaces();
    while(networks.hasMoreElements()) {
      NetworkInterface network = networks.nextElement();
      byte[] mac = network.getHardwareAddress();

      if(mac != null) {
        System.out.print("Current MAC address : ");

        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < mac.length; i++) {
          sb.append(String.format("%02X%s", mac[i], (i < mac.length - 1) ? "-" : ""));
        }
        System.out.println(sb.toString());
      }
    }
  } catch (UnknownHostException e) {
    e.printStackTrace();
  } catch (SocketException e){
    e.printStackTrace();
  }
}

Here is (a sanitized version of) what I see on my computer when I run it:

Current IP address : {I'm not telling :)}
Current MAC address : 
Current MAC address : {actual hardware interface}
Current MAC address : 00-00-00-00-00-00-00-E0
Current MAC address : 00-00-00-00-00-00-00-E0
Current MAC address : 00-00-00-00-00-00-00-E0
Current MAC address : 00-00-00-00-00-00-00-E0
Current MAC address : 00-00-00-00-00-00-00-E0
Current MAC address : 00-50-56-C0-00-01
Current MAC address : 00-50-56-C0-00-08

And here is the output of running ipconfig /all

C:\>ipconfig /all

Windows IP Configuration (minus any actual interface because I don't like sharing that kind of information :)

Ethernet adapter Local Area Connection 2:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Gbridge Virtual Private Network Adapter
   Physical Address. . . . . . . . . : 02-50-F2-CE-82-01
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes

Ethernet adapter VMware Network Adapter VMnet1:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : VMware Virtual Ethernet Adapter for VMnet1
   Physical Address. . . . . . . . . : 00-50-56-C0-00-01
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::9c27:3d03:da2c:f14d%19(Preferred)
   Autoconfiguration IPv4 Address. . : {Hidden}(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.0.0
   Default Gateway . . . . . . . . . :
   DHCPv6 IAID . . . . . . . . . . . : 268456022
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-13-DB-D9-CB-B8-AC-6F-AF-9D-F2
   DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1
                                       fec0:0:0:ffff::2%1
                                       fec0:0:0:ffff::3%1
   NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter VMware Network Adapter VMnet8:

   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : VMware Virtual Ethernet Adapter for VMnet8
   Physical Address. . . . . . . . . : 00-50-56-C0-00-08
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::cdbb:434:7fd9:2574%20(Preferred)
   IPv4 Address. . . . . . . . . . . : 192.168.42.1(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . :
   DHCPv6 IAID . . . . . . . . . . . : 285233238
   DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-13-DB-D9-CB-B8-AC-6F-AF-9D-F2
   DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1
                                       fec0:0:0:ffff::2%1
                                       fec0:0:0:ffff::3%1
   NetBIOS over Tcpip. . . . . . . . : Enabled

Tunnel adapter 6TO4 Adapter:

   Description . . . . . . . . . . . : Microsoft 6to4 Adapter
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes
   IPv6 Address. . . . . . . . . . . : 2002:204c:1bc6::204c:1bc6(Preferred)
   Default Gateway . . . . . . . . . :
   NetBIOS over Tcpip. . . . . . . . : Disabled

Tunnel adapter isatap.{3E45CB42-BC1E-4F89-9C16-25166C0EABA1}:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Microsoft ISATAP Adapter
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes

Tunnel adapter isatap.{77F1FADC-02BA-44AF-9FDF-97E23F8B5FE7}:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Microsoft ISATAP Adapter #3
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes

Tunnel adapter isatap.{608257AC-C0F3-43A5-8595-898533C95D90}:

   Media State . . . . . . . . . . . : Media disconnected
   Connection-specific DNS Suffix  . :
   Description . . . . . . . . . . . : Microsoft ISATAP Adapter #5
   Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
   DHCP Enabled. . . . . . . . . . . : No
   Autoconfiguration Enabled . . . . : Yes

The challenge in getting "just one value" from this mess comes from the relationship between InetAddress.getLocalHost().getHostAddress() and the network interfaces themselves. Consider this slight expanded version of the initial program (using this really cool IterableEnumeration utility class):

public static void main(String[] args) throws UnknownHostException, SocketException {
  System.out.println("Current IP address : " + InetAddress.getLocalHost().getHostAddress());

  for(NetworkInterface network : IterableEnumeration.make(NetworkInterface.getNetworkInterfaces())) {
    byte[] mac = network.getHardwareAddress();
    if(mac != null) {
      System.out.print("Current MAC address : ");
      StringBuilder sb = new StringBuilder();
      for (int i = 0; i < mac.length; i++) {
        sb.append(String.format("%02X%s", mac[i], (i < mac.length - 1) ? "-" : ""));
      }
      System.out.println(sb.toString());
      //Bound InetAddress for interface
      for(InetAddress address : IterableEnumeration.make(network.getInetAddresses())) {
        System.out.println("\tBound to:"+address.getHostAddress());
      }
    }
  }
}

If you run this on your computer you will see your current IP address correlates to one adapter but that MAC address of your hardware interface sees it's self as a different IP address. Maybe you can filter out virtual addresses or just find a way to utilize all available addresses.