Systems often run with multiple active network connections, such as wired Ethernet, 802.11 b/g (wireless), and bluetooth. Some applications might need to access this information to perform the particular network activity on a specific connection.

The java.net.NetworkInterface class provides access to this information.

This lesson guides you through some of the more common uses of this class and provides examples that list all the network interfaces on a machine as well as their IP addresses and status.

What Is a Network Interface?

This page describes a network interface and explains why you might want to use it.

Retrieving Network Interfaces

This page contains an example that illustrates how a client program can retrieve all the network interfaces on a machine.

Listing Network Interface Addresses

This page shows you how to list the IP addresses assigned to all the network interfaces on a machine.

Network Interface Parameters

This page shows you how to determine whether a network interface is running or if the network interface is a loopback interface, a point-to-point interface, or a virtual interface. You can also learn how to determine if the interface supports multicasting.