import java.util.*;
import java.lang.*;
import java.io.*;
import java.net.*;

// The main method must be in a class named "Main".
class Main {
    public static void main(String[] args) {
        testConnection("http//192.0.2.1");               // MalformedURLException
        testConnection("http://[Log in to view URL]");    // UnknownHostException
        // testConnection("http://[Log in to view URL]:80");           // NoRouteToHostException (Reserved IP for documentation)
        // testConnection("http://localhost:9999");         // ConnectException (Port not commonly used)
        // testConnection("http://[Log in to view URL]:8080");      // SocketTimeoutException
    }

    private static void testConnection(String urlString) {
        System.out.println("\nTesting connection to: " + urlString);

        try {
            URL url = new URL(urlString);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setConnectTimeout(1000); // 3 seconds timeout
            connection.setReadTimeout(1000);

            connection.connect();
            System.out.println("Successful connection - Code: " + connection.getResponseCode());
        } catch (MalformedURLException e) {
            System.err.println("Error: Malformed URL - " + e.getMessage());
            System.err.println("Exception type: " + e.getClass().getName());
            System.err.println("Potential cause: The URL format is invalid or contains illegal characters.");
        } catch (UnknownHostException e) {
            System.err.println("Error: Unknown host - " + e.getMessage());
            System.err.println("Exception type: " + e.getClass().getName());
            System.err.println("Potential cause: The domain does not exist or is misspelled.");
        } catch (NoRouteToHostException e) {
            System.err.println("Error: No route to host - " + e.getMessage());
            System.err.println("Exception type: " + e.getClass().getName());
            System.err.println("Potential cause: Network routing issue, firewall blocking access, or host is down.");
        } catch (ConnectException e) {
            System.err.println("Error: Connection refused - " + e.getMessage());
            System.err.println("Exception type: " + e.getClass().getName());
            System.err.println("Potential cause: The server is not running, wrong port, or the service is not accepting connections.");
        } catch (SocketTimeoutException e) {
            System.err.println("Error: Timeout occurred - " + e.getMessage());
            System.err.println("Exception type: " + e.getClass().getName());
            System.err.println("Potential cause: Server is taking too long to respond or network is too slow.");
        } catch (IOException e) {
            System.err.println("Error: General I/O error - " + e.getMessage());
            System.err.println("Exception type: " + e.getClass().getName());
            System.err.println("Potential cause: Network connectivity issues or problem with the data transfer.");
        }
    }
}