How to Display the Hostname for an IP Address in Java?

The following program demonstrates How to Display the Hostname for an IP Address in Java.

You can create a Java application that accepts a hostname and displays its IP address using the InetAddress class from the java.net package. The following code shows a simple example.

import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Scanner;

public class HostnameToIPAddress {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        // Prompt the user to enter a hostname
        System.out.print("Enter a hostname: ");
        String hostname = scanner.nextLine();

        try {
            // Get the IP address for the given hostname
            InetAddress ipAddress = InetAddress.getByName(hostname);

            // Display the IP address
            System.out.println("IP Address for " + hostname + ": " + ipAddress.getHostAddress());
        } catch (UnknownHostException e) {
            System.err.println("Unable to resolve the hostname: " + e.getMessage());
        }

        scanner.close();
    }
}

In this program:

We import the necessary classes from the java.net package.
Then, we create a Scanner to accept user input.
After that, we prompt the user to enter a hostname.
Inside a try-catch block, we use InetAddress.getByName(hostname) to resolve the hostname to an IP address. This method may throw a UnknownHostException if the hostname cannot be resolved.
If the hostname is successfully resolved, we use ipAddress.getHostAddress() to get the IP address and display it to the user.
Otherwise, if the hostname cannot be resolved, we catch the UnknownHostException and display an error message.

Now, you can compile and run this Java program. It will prompt you to enter a hostname, and then it will display the corresponding IP address.

Further Reading