How to execute a java application once the server starts

Question

I have created a java application which executes correctly. I want this application to execute everytime I start my server. I have modified my web.xml as shown below
<servlet>
<servlet-name>SendEmail</servlet-name>
<servlet-class>
com.allcorp.alliance.tdocs.servlets.SendEmail</servlet-class>
<init-param>
<param-name>config</param-name>
<param-value>/WEB-INF/struts-config.xml</param-value>
<load-on-startup>1</load-on-startup>
</init-param>
</servlet>
I have extended the class with HttpServlet. When I start the server, I get the message saying the class is being initializing but it does not execute. I want the application to execute. Any idea what I need to do.

Answer 1

BalusC wrote:
Implement ServletContextListener and run the appplication on creation of the ServletContext.Well i understand implementation of ServletContextListener and by overiding contextInitialized(ServletContextEvent se) accordingly can solve the problem.
but you need to consider two cases here first
1).ServletContextListener is not supported by all container especially the minor onces which does not support Servlet 2.3 specification.
2).OP does not have any idea of how to use a Servlet first if you can see he had written his intialization code in the main method.Now how can you expect him to create a listener..... :)
I hope there are no hard issues on what i said this time.
*@OP*
My friend the bad news is that you need to spend bit of time learning about servlets.U'd not be writing intialization code inside a main rather you'd be doing it inside public void init(ServletConfig config) method.
by making <load-on-startup><!--value</load-on-startup> in web.xml enables Servlet container to call init method at the time of deployment of the web application else where it'd call the init method whenever servlet encounters first request from a client.
package com.allcorp.alliance.tdocs.servlets;
import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.servlet.http.*;
import javax.servlet.*;
import javax.activation.*;
* @author ssa3z
* TODO To change the template for this generated type comment go to
* Window - Preferences - Java - Code Style - Code Templates
public class SendEmail extends HttpServlet{
public void init(ServletConfig config) {
    // SUBSTITUTE YOUR EMAIL ADDRESSES HERE!!!
    String to = "[email protected]";
    String from = "[email protected]";
    // SUBSTITUTE YOUR ISP'S MAIL SERVER HERE!!!
    String host = "smtp.allstate.com";
    // Create properties, get Session
    Properties props = new Properties();
   // If using static Transport.send(),
  // need to specify which host to send it to
  props.put("mail.smtp.host", host);
  // To see what is going on behind the scene
  props.put("mail.debug", "true");
  Session session = Session.getInstance(props);
  try {
     // Instantiatee a message
     Message msg = new MimeMessage(session);
     //Set message attributes
     msg.setFrom(new InternetAddress(from));
     InternetAddress[] address = {new InternetAddress(to)};
     msg.setRecipients(Message.RecipientType.TO, address);
     msg.setSubject("Test E-Mail through Java");
     msg.setSentDate(new Date());
     // Set message content
     msg.setText("This is a test of sending a " +"plain text e-mail through Java.\n" +"Here is line 2.");
     //Send the message
     Transport.send(msg);
  }catch (MessagingException mex) {
    mex.printStackTrace();
} Hope this might help :)
REGARDS,
RaHuL