Checking Internet connectivity using Java can be done using 2 methods:
1) by using getRuntime() method of java Runtime class.
2) by using methods of java URL and URLConnection classes.
#Java Runtime Class:This class is used to interact with java runtime environment (Java virtual machine) in which the application is running. It provides methods/functions to execute a process or a command, invoke garbage collector, get total and free memory in the JVM etc.
#getRuntime():This method of java runtime class returns the runtime object associated with the current java application.
you can learn more about this class here
#Java URL Class:This class provides methods that returns various information like protocol, hostname, file Name, port Number etc of the URL.
#Java URLConnection class:It represents a link between URL and application and can be used to read and write data to the specified resource referred by the URL.
#openConnection():This method of java URLConnection class opens the connection to the specified URL.
you can learn more about these classes here and here
NOTE: Provided method should be run on a local machine and not on an online compiler.
METHOD 1:
Output by this method will be 0 if the internet is connected and it will be 1 if the internet is not connected.
// Java program for Checking Internet connectivityimport java.util.*;import java.io.*;  class checking_internet_connectivity {    public static void main(String args[]) throws Exception    {        Process process = java.lang.Runtime.getRuntime().exec("ping www.geeksforgeeks.org");        int x = process.waitFor();        if (x == 0) {            System.out.println("Connection Successful, "                               + "Output was " + x);        }        else {            System.out.println("Internet Not Connected, "                               + "Output was " + x);        }    }} |
OUTPUT:
METHOD 2:
If Internet is not connected it will throw an exception and catch will execute printing respective message.
// Java program for checking Internet connectivityimport java.util.*;import java.io.*;import java.net.URL;import java.net.URLConnection;Â Â class checking_internet_connectivity {Â Â Â Â public static void main(String args[])Â Â Â Â {Â Â Â Â Â Â Â Â try {Â Â Â Â Â Â Â Â Â Â Â Â URLConnection connection = url.openConnection();Â Â Â Â Â Â Â Â Â Â Â Â connection.connect();Â Â Â Â Â Â Â Â Â Â Â Â Â Â System.out.println("Connection Successful");Â Â Â Â Â Â Â Â }Â Â Â Â Â Â Â Â catch (Exception e) {Â Â Â Â Â Â Â Â Â Â Â Â System.out.println("Internet Not Connected");Â Â Â Â Â Â Â Â }Â Â Â Â }} |
OUTPUT:
