<div>
    <form action="getmail" class="ui-form" method="post">
        <p><input type="submit" value="Загрузить письма с почтового сервиса"></p>
        <p align="left">${connection}</p>
    </form>
</div>

// get mails from imap-server and write mails to hdd

@WebServlet(urlPatterns = {"/getmail"})
public class GetMail extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) {
        try {
		      ..... много всякого
            int connct = MailImap.getMail(imapserver, login, pass, fullPathToFile, pathToRootDir, loadmails, delmails);
			...... 
			// тут нужен индикатор загрузки писем
            request.setAttribute("connection", "Контроль подключения к серверу: " + connct + " Письмо");
            request.getRequestDispatcher("WEB-INF/operator/operator.jsp").forward(request, response);

        } catch (IOException exc) {
        } catch (ServletException exc) {
    }
}
}

// receive mails by IMAP protocol + SSL, all works, but google

public class MailImap {

    public static int getMail(String imapHost, String login, String password, String fullPathToFile, String pathToRootDir,
                              boolean recMail, boolean delMail) {
        try {
            /* create properties field */
                 ......
            /* create the IMAP store object and connect with the imap server */
                .......
            /* create the folder object and open it */
			.........
            /* retrieve the messages from the folder in array*/
            mailsCnt = messages.length;

            if (mailsCnt > 0) {

                if (recMail) {
                    /* allow recieve mails */
                    for (Message message : messages) {
                        /*write mails to dir */
                        SaveMailToDir.saveFile(fullPathToFile, fileName, pathToRootDir, fullMail);
                    }
                }
            }
            /* delete ALL mails */
            /* set FLAGs to delete if delMail == true */
            /* close the store and folder objects */
            return mailsCnt;

        } catch (NoSuchProviderException exc) {
        } catch (AuthenticationFailedException exc) {
        } catch (MessagingException exc) {
        } catch (IOException exc) {
        } catch (Exception exc) {
        }
        return -1;
    }
}

// write mails to hdd

public class SaveMailToDir {

    public static void saveFile(String fullPathToFile, String filename, String pathToRootDir, InputStream input) {
        try {

        } catch (IOException exc) {
        }
    }
}