import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Properties;
import java.util.concurrent.TimeUnit;
import javax.mail.*;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

class URLUtils1 {
String Url = "http://www.gaoogle.com/";
void checkIfURLExists() throws InterruptedException {
    HttpURLConnection httpUrlConn;
    try {
        httpUrlConn = (HttpURLConnection) new URL(Url)
                .openConnection();
        httpUrlConn.setRequestMethod("HEAD");


        httpUrlConn.setConnectTimeout(30000);
        httpUrlConn.setReadTimeout(30000);



        if (httpUrlConn.getResponseCode() == HttpURLConnection.HTTP_OK)
        {
            System.out.println("Working");

            recall();
        }
    } catch (IOException | InterruptedException e) {
        System.out.println("Error: " + e.getMessage());
        System.out.println("Not Working");
        recallondead();
    }
}

void recall() throws InterruptedException {
    TimeUnit.MINUTES.sleep(1);
    checkIfURLExists();
}


void recallondead() throws InterruptedException {




    final String username = "senderxxx@gmail.com";
    final String password = "senderpass";

    Properties props = new Properties();
    props.put("mail.smtp.auth", "true");
    props.put("mail.smtp.starttls.enable", "true");
    props.put("mail.smtp.host", "smtp.gmail.com");
    props.put("mail.smtp.port", "587");
            props.put("mail.smtp.ssl.trust", "smtp.gmail.com");


    Session session = Session.getInstance(props,
      new javax.mail.Authenticator() {
        protected PasswordAuthentication getPasswordAuthentication() {
            return new PasswordAuthentication(username, password);
        }
      });

    try {

        Message message = new MimeMessage(session);
        message.setFrom(new InternetAddress("sender@gmail.com"));
        message.setRecipients(Message.RecipientType.TO,
            InternetAddress.parse("reciever@gmail.com"));
        message.setSubject("Website "+Url+" Is Down");
        message.setText("Dear Sir,"
            + "nn Website "+Url+" Is down");

        Transport.send(message);

        System.out.println("Error..!  Mail Sent");

    } catch (MessagingException e) {
        throw new RuntimeException(e);
    }


    TimeUnit.MINUTES.sleep(5);
    checkIfURLExists();
}

}

class URLUtils
{
public static void main(String[] args) throws InterruptedException {
    URLUtils1 ab = new URLUtils1();

    ab.checkIfURLExists();
}
}