networking - How to get subnet mask of local system using java?

Question

How do you get the Subnet mask address of the local system using Java?

Answer 1

the netmask of the first address of the localhost interface:

InetAddress localHost = Inet4Address.getLocalHost();
NetworkInterface networkInterface = NetworkInterface.getByInetAddress(localHost);
networkInterface.getInterfaceAddresses().get(0).getNetworkPrefixLength();

a more complete approach:

InetAddress localHost = Inet4Address.getLocalHost();
NetworkInterface networkInterface = NetworkInterface.getByInetAddress(localHost);

for (InterfaceAddress address : networkInterface.getInterfaceAddresses()) {
    System.out.println(address.getNetworkPrefixLength());
}

/24 means 255.255.255.