Replying email in Java Mail API

In this chapter we will see how to reply to an email using JavaMail API.

We can forward the received mail to someone else as we send emails. There are many javamail classes that are used to forward the messages to the destination resource.

For better understanding of this example, learn the steps of sending email using JavaMail API first.

For receiving or sending the email using JavaMail API, you need to load the two jar files:
  • mail.jar
  • activation.jar

Create Java Class

Create a java class file ReplyToEmail, the contents of which are as follows:

import java.util.*;  
import javax.mail.*;  
import javax.mail.internet.*;  
public class ReplyToEmail {
 public static void main(String[] args) {
  Properties props = new Properties();
  props.put("mail.smtp.host", "smtp.gmail.com");
  props.put("mail.smtp.socketFactory.port", "465");
  props.put("mail.smtp.auth", "true");
  props.put("mail.smtp.port", "465");
  final String username="admin@dineshonjava.com";
  final String password="******";
  Session session = Session.getDefaultInstance(props,
   new javax.mail.Authenticator() {
    protected PasswordAuthentication getPasswordAuthentication() {
     return new PasswordAuthentication(username,password);
  try {
  Store store = session.getStore("imaps");  
  store.connect("imap.gmail.com",username, password);  
  //Create a Folder object and open the folder  
  Folder folder = store.getFolder("inbox");  
     Message message = folder.getMessage(10);  
    // Get all the information from the message  
    String from = InternetAddress.toString(message.getFrom());  
    if (from != null) {  
   System.out.println("From: " + from);  
    String replyTo = InternetAddress.toString(message.getReplyTo());  
    if (replyTo != null) {  
   System.out.println("Reply-to: " + replyTo);  
    String to = InternetAddress.toString(message.getRecipients(Message.RecipientType.TO));  
    if (to != null) {  
   System.out.println("To: " + to);  
    String subject = message.getSubject();  
   if (subject != null) {  
  System.out.println("Subject: " + subject);  
   Date sent = message.getSentDate();  
   if (sent != null) {  
  System.out.println("Sent: " + sent);  
   // compose the message to forward  
   Message message2 = new MimeMessage(session);  
    message2= (MimeMessage) message.reply(false);
   message2.setSubject("RE: " + message.getSubject());  
   message2.setFrom(new InternetAddress(from));  

   message2.addRecipient(Message.RecipientType.TO, new InternetAddress(to));  
   // Create your new message part  
   BodyPart messageBodyPart = new MimeBodyPart();  
   messageBodyPart.setText("Oiginal message:\n\n");  
   // Create a multi-part to combine the parts  
   Multipart multipart = new MimeMultipart();  
   // Create and fill part for the forwarded content  
   messageBodyPart = new MimeBodyPart();  
   // Add part to multi part  
   // Associate multi-part with message  
   // Send message  
   System.out.println("message replied successfully ....");  
   } catch (Exception e) {
   throw new RuntimeException(e);

Compile and Run

Now that our class is ready, let us compile the above class. I've saved the class ReplyToEmail.java to directory : D:\Javas\mailapi\. We would need the jars javax.mail.jar and activation.jar in the classpath. Execute the command below to compile the class

Replying email in Java Mail API

Verify Output

You should see the following message on the command console:
From: Anonymous <noreply-comment@blogger.com>
Reply-to: Anonymous <noreply-comment@blogger.com>
To: admin@dineshonjava.com
Subject: [Dinesh on Java] New comment on Writing First AspectJ Program in Spring
 : Chapter ....
Sent: Wed Dec 19 10:29:12 IST 2012
message replied successfully ....

Replying email in Java Mail

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