You can use Java’s InetAddress class to check internet connectivity and ping a server directly. Here is how you can do it:

Steps to check internet connectivity and ping a server:

1. Use InetAddress.getByName(String host) or InetAddress.getByAddress(...) to get the address of the host/server you want to ping.
2. Use the isReachable(int timeout) method to test if the server is reachable within a specified timeout.

Example Code:

package org.kodejava.net;

import java.net.InetAddress;

public class InternetConnectivityChecker {
   public static void main(String[] args) {
      String server = "www.google.com"; // Replace with the server you want to ping
      int timeout = 5000; // Timeout in milliseconds

      try {
         // Get the InetAddress of the server
         InetAddress inetAddress = InetAddress.getByName(server);

         System.out.println("Pinging " + server + " (" + inetAddress.getHostAddress() + ")...");

         // Check if the server is reachable
         boolean isReachable = inetAddress.isReachable(timeout);

         if (isReachable) {
            System.out.println(server + " is reachable.");
         } else {
            System.out.println(server + " is not reachable.");
         }
      } catch (Exception e) {
         System.out.println("Error occurred: " + e.getMessage());
      }
   }
}

Explanation:

1. InetAddress.getByName(String host):
   • Resolves the hostname (e.g., “www.google.com“) into its IP address.
2. isReachable(int timeout):
   • Tests whether the specified server can be reached within the given timeout.
   • Internally, it uses ICMP “ping” requests or a TCP connection.
3. Timeout:
   • The isReachable method will try to reach the server and wait until the specified timeout (in milliseconds). If the server does not respond within that time, it returns false.

Notes:

1. Administrator Privileges: On some systems (like Windows), the isReachable method might require administrator privileges to send ICMP requests.
2. Fallback: If ICMP is not supported, isReachable may use a TCP connection to the host at port 7 (echo).

Sample Output:

If the server is reachable:

Pinging www.google.com (142.250.190.68)...
www.google.com is reachable.

If the server is not reachable:

Pinging www.google.com (142.250.190.68)...
www.google.com is not reachable.

Alternatives:

If you need more robust and versatile methods for checking connectivity (like using HTTP), you could use Java’s HttpURLConnection to make a simple HTTP request instead of relying solely on InetAddress.