i got this code from a site ... it is compiled successfully but gives an exception "java.net.UnknownHostException: mailhost"
does it mean that i need a Mail Server to execute this code? ... if YES, then where i can find a mail server, plz give me a web link ... if NO, then what iz the problem with this code ... plz guide me bcoz i m new in this field

import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;

import com.oreilly.servlet.ParameterParser;
import com.oreilly.servlet.ServletUtils;

import sun.net.smtp.SmtpClient;

public class MailServlet extends HttpServlet {

  static final String FROM = "[email protected]";
  static final String TO = "[email protected]";

  public void doGet(HttpServletRequest req, HttpServletResponse res)
                               throws ServletException, IOException {
    res.setContentType("text/plain");
    PrintWriter out = res.getWriter();

    ParameterParser parser = new ParameterParser(req);
    String from = parser.getStringParameter("from", FROM);
    String to = parser.getStringParameter("to", TO);

    try {
      SmtpClient smtp = new SmtpClient(); // assume localhost
      smtp.from(from);
      smtp.to(to);
      PrintStream msg = smtp.startMessage();

      msg.println("To: " + to); // so mailers will display the To: address
      msg.println("Subject: just checking...");
      msg.println();

      Enumeration enm = req.getParameterNames();
      while (enm.hasMoreElements()) {
        String name = (String)enm.nextElement();
        if (name.equals("to") || name.equals("from")) continue; // Skip to/from
        String value = parser.getStringParameter(name, null);
        msg.println(name + " = " + value);
      }

      msg.println();
      msg.println("---");
      msg.println("Sent by " + HttpUtils.getRequestURL(req));

      smtp.closeServer();

      out.println("Thanks for the submission...");
    }
    catch (Exception e) {
        e.printStackTrace();
      out.println("There was a problem handling the submission...");
      getServletContext().log(e, "There was a problem sending email");
    }
  }
}