JavaMail API - Quick Guide

The JavaMail API provides a platform-independent and protocol-independent framework to build mail and messaging applications. The JavaMail API provides a set of abstract classes defining objects that comprise a mail system. It is an optional package (standard extension) for reading, composing, and sending electronic messages.

JavaMail provides elements that are used to construct an interface to a messaging system, including system components and interfaces. While this specification does not define any specific implementation, JavaMail does include several classes that implement RFC822 and MIME Internet messaging standards. These classes are delivered as part of the JavaMail class package.

Following are some of the protocols supported in JavaMail API:

• SMTP: Acronym for Simple Mail Transfer Protocol. It provides a mechanism to deliver email.

• POP: Acronym for Post Office Protocol. POP is the mechanism most people on the Internet use to get their mail. It defines support for a single mailbox for each user. RFC 1939 defines this protocol.

• IMAP: Acronym for Internet Message Access Protocol. It is an advanced protocol for receiving messages. It provides support for multiple mailbox for each user, in addition to, mailbox can be shared by multiple users. It is defined in RFC 2060.

• MIME: Acronym for Multipurpose Internet Mail Extensions. . It is not a mail transfer protocol. Instead, it defines the content of what is transferred: the format of the messages, attachments, and so on. There are many different documents that take effect here: RFC 822, RFC 2045, RFC 2046, and RFC 2047. As a user of the JavaMail API, you usually don't need to worry about these formats. However, these formats do exist and are used by your programs.

• NNTP and Others:There are many protocols that are provided by third-party providers. Some of them are Network News Transfer Protocol (NNTP), Secure Multipurpose Internet Mail Extensions (S/MIME) etc.

Details of these will be covered in the subsequent chapters.

Architecture

As said above the java application uses JavaMail API to compose, send and receive emails.The following figure illustrates the architecture of JavaMail:

The abstract mechanism of JavaMail API is similar to other J2EE APIs, such as JDBC, JNDI, and JMS. As seen the architecture diagram above, JavaMail API is divided into two main parts:

• An application-independent part: An application-programming interface (API) is used by the application components to send and receive mail messages, independent of the underlying provider or protocol used.

• A service-dependent part: A service provider interface (SPI) speaks the protocol-specific languages, such as SMTP, POP, IMAP, and Network News Transfer Protocol (NNTP). It is used to plug in a provider of an e-mail service to the J2EE platform.

Environment Setup

To send an e-mail using your Java Application is simple enough but to start with you should have JavaMail API and Java Activation Framework (JAF) installed on your machine.

You will need the JavaBeans Activation Framework (JAF) extension that provides the javax.activation package only when you're not using Java SE 6 or newer.

• You can download latest version of JavaMail (Version 1.5.0) from Java's standard website.

• You can download latest version of JAF (Version 1.1.1) from Java's standard website.

Download and unzip these files, in the newly created top level directories you will find a number of jar files for both the applications. You need to add mail.jar and activation.jar files in your CLASSPATH.

SMTP server

To send emails, you must have SMTP server that is responsible to send mails. You can use one of the following techniques to get the SMTP server:

• Install and use any SMTP server such as Postfix server (for Ubuntu), Apache James server (Java Apache Mail Enterprise Server)etc. (or)

• Use the SMTP server provided by the host provider for eg: free SMTP provide by JangoSMTP site is relay.jangosmtp.net (or)

• Use the SMTP Server provided by companies e.g. gmail, yahoo, etc.

The examples in the subsequent chapters, we've used the free JangoSMTP server to send email. You can create an account by visiting this site and configure your email adress.

Core Classes

The JavaMail API consists of some interfaces and classes used to send, read, and delete e-mail messages. Though there are many packages in the JavaMail API, will cover the main two packages that are used in Java Mail API frequently: javax.mail and javax.mail.internet package. These packages contain all the JavaMail core classes. They are:

Sending Simple Emails

Here is an example to send a simple email. Here we have used JangoSMTP server via which emails are sent to our destination email address. The setup is explained in the Environment Setup chapter.

To send a simple email steps followed are:

• Get a Session

• Create a default MimeMessage object and set From, To, Subject in the message.

• Set the actual message as:

  message.setText("your text goes here");
  

• Send the message using the Transport object.

Create Java Class

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

package com.howcodex;

import java.util.Properties;

import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

public class SendEmail {
   public static void main(String[] args) {
      // Recipient's email ID needs to be mentioned.
      String to = "destinationemail@gmail.com";

      // Sender's email ID needs to be mentioned
      String from = "fromemail@gmail.com";
      final String username = "manishaspatil";//change accordingly
      final String password = "******";//change accordingly

      // Assuming you are sending email through relay.jangosmtp.net
      String host = "relay.jangosmtp.net";

      Properties props = new Properties();
      props.put("mail.smtp.auth", "true");
      props.put("mail.smtp.starttls.enable", "true");
      props.put("mail.smtp.host", host);
      props.put("mail.smtp.port", "25");

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

      try {
	   // Create a default MimeMessage object.
	   Message message = new MimeMessage(session);
	
	   // Set From: header field of the header.
	   message.setFrom(new InternetAddress(from));
	
	   // Set To: header field of the header.
	   message.setRecipients(Message.RecipientType.TO,
               InternetAddress.parse(to));
	
	   // Set Subject: header field
	   message.setSubject("Testing Subject");
	
	   // Now set the actual message
	   message.setText("Hello, this is sample for to check send " +
		"email using JavaMailAPI ");

	   // Send message
	   Transport.send(message);

	   System.out.println("Sent message successfully....");

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

As we are using the SMTP server provided by the host provider JangoSMTP, we need to authenticate the username and password. The javax.mail.PasswordAuthentication class is used to authenticate the password.

Compile and Run

Now that our class is ready, let us compile the above class. I've saved the class SendEmail.java to directory : /home/manisha/JavaMailAPIExercise. We would need the jars javax.mail.jar and activation.jar in the classpath. Execute the command below to compile the class (both the jars are placed in /home/manisha/ directory) from command prompt:

javac -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: SendEmail.java

Now that the class is compiled, execute the below command to run:

java -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: SendEmail

Verify Output

You should see the following message on the command console:

Sent message successfully....

As I'm sending an email to my gmail address through JangoSMTP, the following mail would be received in my gmail account inbox:

Sending Email With Attachment

Here is an example to send an email with attachment from your machine. The file on local machine is file.txt placed at /home/manisha/. Here we have used JangoSMTP server via which emails are sent to our destination email address. The setup is explained in the Environment Setup chapter.

To send a email with an inline image, the steps followed are:

• Get a Session

• Create a default MimeMessage object and set From, To, Subject in the message.

• Set the actual message as below:

  messageBodyPart.setText("This is message body");
  

• Create a MimeMultipart object. Add the above messageBodyPart with actual message set in it, to this multipart object.

• Next add the attachment by creating a Datahandler as follows:

  messageBodyPart = new MimeBodyPart();
  String filename = "/home/manisha/file.txt";
  DataSource source = new FileDataSource(filename);
  messageBodyPart.setDataHandler(new DataHandler(source));
  messageBodyPart.setFileName(filename);
  multipart.addBodyPart(messageBodyPart);
  

• Next set the multipart in the message as follows:

  message.setContent(multipart);
  

• Send the message using the Transport object.

Create Java Class

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

package com.howcodex;

import java.util.Properties;

import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.activation.FileDataSource;
import javax.mail.BodyPart;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;

public class SendAttachmentInEmail {
   public static void main(String[] args) {
      // Recipient's email ID needs to be mentioned.
      String to = "destinationemail@gmail.com";

      // Sender's email ID needs to be mentioned
      String from = "fromemail@gmail.com";

      final String username = "manishaspatil";//change accordingly
      final String password = "******";//change accordingly

      // Assuming you are sending email through relay.jangosmtp.net
      String host = "relay.jangosmtp.net";

      Properties props = new Properties();
      props.put("mail.smtp.auth", "true");
      props.put("mail.smtp.starttls.enable", "true");
      props.put("mail.smtp.host", host);
      props.put("mail.smtp.port", "25");

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

      try {
         // Create a default MimeMessage object.
         Message message = new MimeMessage(session);

         // Set From: header field of the header.
         message.setFrom(new InternetAddress(from));

         // Set To: header field of the header.
         message.setRecipients(Message.RecipientType.TO,
            InternetAddress.parse(to));

         // Set Subject: header field
         message.setSubject("Testing Subject");

         // Create the message part
         BodyPart messageBodyPart = new MimeBodyPart();

         // Now set the actual message
         messageBodyPart.setText("This is message body");

         // Create a multipar message
         Multipart multipart = new MimeMultipart();

         // Set text message part
         multipart.addBodyPart(messageBodyPart);

         // Part two is attachment
         messageBodyPart = new MimeBodyPart();
         String filename = "/home/manisha/file.txt";
         DataSource source = new FileDataSource(filename);
         messageBodyPart.setDataHandler(new DataHandler(source));
         messageBodyPart.setFileName(filename);
         multipart.addBodyPart(messageBodyPart);

         // Send the complete message parts
         message.setContent(multipart);

         // Send message
         Transport.send(message);

         System.out.println("Sent message successfully....");
  
      } catch (MessagingException e) {
         throw new RuntimeException(e);
      }
   }
}

As we are using the SMTP server provided by the host provider JangoSMTP, we need to authenticate the username and password. The javax.mail.PasswordAuthentication class is used to authenticate the password.

Compile and Run

Now that our class is ready, let us compile the above class. I've saved the class SendAttachmentInEmail.java to directory : /home/manisha/JavaMailAPIExercise. We would need the jars javax.mail.jar and activation.jar in the classpath. Execute the command below to compile the class (both the jars are placed in /home/manisha/ directory) from command prompt:

javac -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: SendAttachmentInEmail.java

Now that the class is compiled, execute the below command to run:

java -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: SendAttachmentInEmail

Verify Output

You should see the following message on the command console:

Sent message successfully....

As I'm sending an email to my gmail address through JangoSMTP, the following mail would be received in my gmail account inbox:

Sending an HTML Email

Here is an example to send an HTML email from your machine. Here we have used JangoSMTP server via which emails are sent to our destination email address. The setup is explained in the Environment Setup chapter.

This example is very similar to sending simple email, except that, here we are using setContent() method to set content whose second argument is "text/html" to specify that the HTML content is included in the message. Using this example, you can send as big as HTML content you like.

To send a email with HTML content, the steps followed are:

• Get a Session

• Create a default MimeMessage object and set From, To, Subject in the message.

• Set the actual message using setContent() method as below:

  message.setContent("<h1>This is actual message embedded in 
     HTML tags</h1>", "text/html");
  

• Send the message using the Transport object.

Create Java Class

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

package com.howcodex;

import java.util.Properties;

import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

public class SendHTMLEmail {
   public static void main(String[] args) {
      // Recipient's email ID needs to be mentioned.
      String to = "destinationemail@gmail.com";

      // Sender's email ID needs to be mentioned
      String from = "fromemail@gmail.com";
      final String username = "manishaspatil";//change accordingly
      final String password = "******";//change accordingly

      // Assuming you are sending email through relay.jangosmtp.net
      String host = "relay.jangosmtp.net";

      Properties props = new Properties();
      props.put("mail.smtp.auth", "true");
      props.put("mail.smtp.starttls.enable", "true");
      props.put("mail.smtp.host", host);
      props.put("mail.smtp.port", "25");

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

      try {
            // Create a default MimeMessage object.
            Message message = new MimeMessage(session);

   	   // Set From: header field of the header.
	   message.setFrom(new InternetAddress(from));

	   // Set To: header field of the header.
	   message.setRecipients(Message.RecipientType.TO,
              InternetAddress.parse(to));

	   // Set Subject: header field
	   message.setSubject("Testing Subject");

	   // Send the actual HTML message, as big as you like
	   message.setContent(
              "<h1>This is actual message embedded in HTML tags</h1>",
             "text/html");

	   // Send message
	   Transport.send(message);

	   System.out.println("Sent message successfully....");

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

As we are using the SMTP server provided by the host provider JangoSMTP, we need to authenticate the username and password. The javax.mail.PasswordAuthentication class is used to authenticate the password.

Compile and Run

Now that our class is ready, let us compile the above class. I've saved the class SendHTMLEmail.java to directory : /home/manisha/JavaMailAPIExercise. We would need the jars javax.mail.jar and activation.jar in the classpath. Execute the command below to compile the class (both the jars are placed in /home/manisha/ directory) from command prompt:

javac -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: SendHTMLEmail.java

Now that the class is compiled, execute the below command to run:

java -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: SendHTMLEmail

Verify Output

You should see the following message on the command console:

Sent message successfully....

As I'm sending an email to my gmail address through JangoSMTP, the following mail would be received in my gmail account inbox:

Sending Email With Inline Images

Here is an example to send an HTML email from your machine with inline image. Here we have used JangoSMTP server via which emails are sent to our destination email address. The setup is explained in the Environment Setup chapter.

To send a email with an inline image, the steps followed are:

• Get a Session

• Create a default MimeMessage object and set From, To, Subject in the message.

• Create a MimeMultipart object.

• In our example we will have an HTML part and an Image in the email. So first create the HTML content and set it in the multipart object as:

  // first part (the html)
  BodyPart messageBodyPart = new MimeBodyPart();
  String htmlText = "<H1>Hello</H1><img src=\"cid:image\">";
  messageBodyPart.setContent(htmlText, "text/html");
  // add it
  multipart.addBodyPart(messageBodyPart);
  

• Next add the image by creating a Datahandler as follows:

  // second part (the image)
  messageBodyPart = new MimeBodyPart();
  DataSource fds = new FileDataSource(
   "/home/manisha/javamail-mini-logo.png");
  
  messageBodyPart.setDataHandler(new DataHandler(fds));
  messageBodyPart.setHeader("Content-ID", "<image>");
  

• Next set the multipart in the message as follows:

  message.setContent(multipart);
  

• Send the message using the Transport object.

Create Java Class

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

package com.howcodex;

import java.util.Properties;
import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.activation.FileDataSource;
import javax.mail.BodyPart;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;

public class SendInlineImagesInEmail {
   public static void main(String[] args) {
      // Recipient's email ID needs to be mentioned.
      String to = "destinationemail@gmail.com";

      // Sender's email ID needs to be mentioned
      String from = "fromemail@gmail.com";
      final String username = "manishaspatil";//change accordingly
      final String password = "******";//change accordingly

      // Assuming you are sending email through relay.jangosmtp.net
      String host = "relay.jangosmtp.net";

      Properties props = new Properties();
      props.put("mail.smtp.auth", "true");
      props.put("mail.smtp.starttls.enable", "true");
      props.put("mail.smtp.host", host);
      props.put("mail.smtp.port", "25");

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

      try {

         // Create a default MimeMessage object.
         Message message = new MimeMessage(session);

         // Set From: header field of the header.
         message.setFrom(new InternetAddress(from));

         // Set To: header field of the header.
         message.setRecipients(Message.RecipientType.TO,
            InternetAddress.parse(to));

         // Set Subject: header field
         message.setSubject("Testing Subject");

         // This mail has 2 part, the BODY and the embedded image
         MimeMultipart multipart = new MimeMultipart("related");

         // first part (the html)
         BodyPart messageBodyPart = new MimeBodyPart();
         String htmlText = "<H1>Hello</H1><img src=\"cid:image\">";
         messageBodyPart.setContent(htmlText, "text/html");
         // add it
         multipart.addBodyPart(messageBodyPart);

         // second part (the image)
         messageBodyPart = new MimeBodyPart();
         DataSource fds = new FileDataSource(
            "/home/manisha/javamail-mini-logo.png");

         messageBodyPart.setDataHandler(new DataHandler(fds));
         messageBodyPart.setHeader("Content-ID", "<image>");

         // add image to the multipart
         multipart.addBodyPart(messageBodyPart);

         // put everything together
         message.setContent(multipart);
         // Send message
         Transport.send(message);

         System.out.println("Sent message successfully....");

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

As we are using the SMTP server provided by the host provider JangoSMTP, we need to authenticate the username and password. The javax.mail.PasswordAuthentication class is used to authenticate the password.

Compile and Run

Now that our class is ready, let us compile the above class. I've saved the class SendInlineImagesInEmail.java to directory : /home/manisha/JavaMailAPIExercise. We would need the jars javax.mail.jar and activation.jar in the classpath. Execute the command below to compile the class (both the jars are placed in /home/manisha/ directory) from command prompt:

javac -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: SendInlineImagesInEmail.java

Now that the class is compiled, execute the below command to run:

java -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: SendInlineImagesInEmail

Verify Output

You should see the following message on the command console:

Sent message successfully....

As I'm sending an email to my gmail address through JangoSMTP, the following mail would be received in my gmail account inbox:

Checking Emails

There are two aspects to which needs to understood before proceeding with this chapter. They are Check and Fetch.

• Checking an email in JavaMail is a process where we open the respective folder in the mailbox and get each message. Here we only check the header of each message i.e the From, To, subject. Content is not read.

• Fetching an email in JavaMail is a process where we open the respective folder in the mailbox and get each message. Alongwith the header we also read the content by recognizing the content-type.

To check or fetch an email using JavaMail API, we would need POP or IMAP servers. To check and fetch the emails, Folder and Store classes are needed. Here we have used GMAIL's POP3 server (pop.gmail.com). In this chapter will learn how to check emails using JavaMail API. Fetching shall be covered in the subsequent chapters. To check emails:

• Get a Session

• Create pop3 Store object and connect with pop server.

• Create folder object. Open the appropriate folder in your mailbox.

• Get your messages.

• Close the Store and Folder objects.

Create Java Class

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

package com.howcodex;

import java.util.Properties;

import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.NoSuchProviderException;
import javax.mail.Session;
import javax.mail.Store;

public class CheckingMails {

   public static void check(String host, String storeType, String user,
      String password) 
   {
      try {

      //create properties field
      Properties properties = new Properties();

      properties.put("mail.pop3.host", host);
      properties.put("mail.pop3.port", "995");
      properties.put("mail.pop3.starttls.enable", "true");
      Session emailSession = Session.getDefaultInstance(properties);
  
      //create the POP3 store object and connect with the pop server
      Store store = emailSession.getStore("pop3s");

      store.connect(host, user, password);

      //create the folder object and open it
      Folder emailFolder = store.getFolder("INBOX");
      emailFolder.open(Folder.READ_ONLY);

      // retrieve the messages from the folder in an array and print it
      Message[] messages = emailFolder.getMessages();
      System.out.println("messages.length---" + messages.length);

      for (int i = 0, n = messages.length; i < n; i++) {
         Message message = messages[i];
         System.out.println("---------------------------------");
         System.out.println("Email Number " + (i + 1));
         System.out.println("Subject: " + message.getSubject());
         System.out.println("From: " + message.getFrom()[0]);
         System.out.println("Text: " + message.getContent().toString());

      }

      //close the store and folder objects
      emailFolder.close(false);
      store.close();

      } catch (NoSuchProviderException e) {
         e.printStackTrace();
      } catch (MessagingException e) {
         e.printStackTrace();
      } catch (Exception e) {
         e.printStackTrace();
      }
   }

   public static void main(String[] args) {

      String host = "pop.gmail.com";// change accordingly
      String mailStoreType = "pop3";
      String username = "yourmail@gmail.com";// change accordingly
      String password = "*****";// change accordingly

      check(host, mailStoreType, username, password);

   }

}

Compile and Run

Now that our class is ready, let us compile the above class. I've saved the class CheckingMails.java to directory : /home/manisha/JavaMailAPIExercise. We would need the jars javax.mail.jar and activation.jar in the classpath. Execute the command below to compile the class (both the jars are placed in /home/manisha/ directory) from command prompt:

javac -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: CheckingMails.java

Now that the class is compiled, execute the below command to run:

java -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: CheckingMails

Verify Output

You should see the following message on the command console:

messages.length---4
---------------------------------
Email Number 1
Subject: Test Mail--Fetch
From: <abcd@gmail.com>
Text: javax.mail.internet.MimeMultipart@327a5b7f
---------------------------------
Email Number 2
Subject: testing ----checking simple email
From: <abcd@gmail.com>
Text: javax.mail.internet.MimeMultipart@7f0d08bc
---------------------------------
Email Number 3
Subject: Email with attachment
From: <abcd@gmail.com>
Text: javax.mail.internet.MimeMultipart@30b8afce
---------------------------------
Email Number 4
Subject: Email with Inline image
From: <abcd@gmail.com>
Text: javax.mail.internet.MimeMultipart@2d1e165f

Here we have printed the number of messages in the INBOX which is 4 in this case. We have also printed Subject, From address and Text for each email message.

Fetching Emails

In the previous chapter we learnt how to check emails. Now let us see how to fetch each email and read its content. Let us write a Java class FetchingEmail which will read following types of emails:

• Simple email

• Email with attachment

• Email with inline image

Basic steps followed in the code are as below:

• Get the Session object.

• Create POP3 store object and connect to the store.

• Create Folder object and open the appropriate folder in your mailbox.

• Retrieve messages.

• Close the folder and store objects respectively.

Create Java Class

Create a java Create a java class file FetchingEmail, contents of which are as below:

package com.howcodex;

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Date;
import java.util.Properties;

import javax.mail.Address;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.NoSuchProviderException;
import javax.mail.Part;
import javax.mail.Session;
import javax.mail.Store;

public class FetchingEmail {

   public static void fetch(String pop3Host, String storeType, String user,
      String password) {
      try {
         // create properties field
         Properties properties = new Properties();
         properties.put("mail.store.protocol", "pop3");
         properties.put("mail.pop3.host", pop3Host);
         properties.put("mail.pop3.port", "995");
         properties.put("mail.pop3.starttls.enable", "true");
         Session emailSession = Session.getDefaultInstance(properties);
         // emailSession.setDebug(true);

         // create the POP3 store object and connect with the pop server
         Store store = emailSession.getStore("pop3s");

         store.connect(pop3Host, user, password);

         // create the folder object and open it
         Folder emailFolder = store.getFolder("INBOX");
         emailFolder.open(Folder.READ_ONLY);

         BufferedReader reader = new BufferedReader(new InputStreamReader(
	      System.in));

         // retrieve the messages from the folder in an array and print it
         Message[] messages = emailFolder.getMessages();
         System.out.println("messages.length---" + messages.length);

         for (int i = 0; i < messages.length; i++) {
            Message message = messages[i];
            System.out.println("---------------------------------");
            writePart(message);
            String line = reader.readLine();
            if ("YES".equals(line)) {
               message.writeTo(System.out);
            } else if ("QUIT".equals(line)) {
               break;
            }
         }

         // close the store and folder objects
         emailFolder.close(false);
         store.close();

      } catch (NoSuchProviderException e) {
         e.printStackTrace();
      } catch (MessagingException e) {
         e.printStackTrace();
      } catch (IOException e) {
         e.printStackTrace();
      } catch (Exception e) {
         e.printStackTrace();
      }
}

   public static void main(String[] args) {

      String host = "pop.gmail.com";// change accordingly
      String mailStoreType = "pop3";
      String username = 
         "abc@gmail.com";// change accordingly
      String password = "*****";// change accordingly

      //Call method fetch
      fetch(host, mailStoreType, username, password);

   }

   /*
   * This method checks for content-type 
   * based on which, it processes and
   * fetches the content of the message
   */
   public static void writePart(Part p) throws Exception {
      if (p instanceof Message)
         //Call methos writeEnvelope
         writeEnvelope((Message) p);

      System.out.println("----------------------------");
      System.out.println("CONTENT-TYPE: " + p.getContentType());

      //check if the content is plain text
      if (p.isMimeType("text/plain")) {
         System.out.println("This is plain text");
         System.out.println("---------------------------");
         System.out.println((String) p.getContent());
      } 
      //check if the content has attachment
      else if (p.isMimeType("multipart/*")) {
         System.out.println("This is a Multipart");
         System.out.println("---------------------------");
         Multipart mp = (Multipart) p.getContent();
         int count = mp.getCount();
         for (int i = 0; i < count; i++)
            writePart(mp.getBodyPart(i));
      } 
      //check if the content is a nested message
      else if (p.isMimeType("message/rfc822")) {
         System.out.println("This is a Nested Message");
         System.out.println("---------------------------");
         writePart((Part) p.getContent());
      } 
      //check if the content is an inline image
      else if (p.isMimeType("image/jpeg")) {
         System.out.println("--------> image/jpeg");
         Object o = p.getContent();

         InputStream x = (InputStream) o;
         // Construct the required byte array
         System.out.println("x.length = " + x.available());
         int i = 0;
         byte[] bArray = new byte[x.available()];

         while ((i = (int) ((InputStream) x).available()) > 0) {
            int result = (int) (((InputStream) x).read(bArray));
            if (result == -1)
            break;
         }
         FileOutputStream f2 = new FileOutputStream("/tmp/image.jpg");
         f2.write(bArray);
      } 
      else if (p.getContentType().contains("image/")) {
         System.out.println("content type" + p.getContentType());
         File f = new File("image" + new Date().getTime() + ".jpg");
         DataOutputStream output = new DataOutputStream(
            new BufferedOutputStream(new FileOutputStream(f)));
            com.sun.mail.util.BASE64DecoderStream test = 
                 (com.sun.mail.util.BASE64DecoderStream) p
                  .getContent();
         byte[] buffer = new byte[1024];
         int bytesRead;
         while ((bytesRead = test.read(buffer)) != -1) {
            output.write(buffer, 0, bytesRead);
         }
      } 
      else {
         Object o = p.getContent();
         if (o instanceof String) {
            System.out.println("This is a string");
            System.out.println("---------------------------");
            System.out.println((String) o);
         } 
         else if (o instanceof InputStream) {
            System.out.println("This is just an input stream");
            System.out.println("---------------------------");
            InputStream is = (InputStream) o;
            is = (InputStream) o;
            int c;
            while ((c = is.read()) != -1)
               System.out.write(c);
         } 
         else {
            System.out.println("This is an unknown type");
            System.out.println("---------------------------");
            System.out.println(o.toString());
         }
   }

}
   /*
   * This method would print FROM,TO and SUBJECT of the message
   */
   public static void writeEnvelope(Message m) throws Exception {
      System.out.println("This is the message envelope");
      System.out.println("---------------------------");
      Address[] a;

      // FROM
      if ((a = m.getFrom()) != null) {
         for (int j = 0; j < a.length; j++)
         System.out.println("FROM: " + a[j].toString());
      }

      // TO
      if ((a = m.getRecipients(Message.RecipientType.TO)) != null) {
         for (int j = 0; j < a.length; j++)
         System.out.println("TO: " + a[j].toString());
      }

      // SUBJECT
      if (m.getSubject() != null)
         System.out.println("SUBJECT: " + m.getSubject());

   }

}

You can set the debug on by uncommenting the statement emailSession.setDebug(true);

Compile and Run

Now that our class is ready, let us compile the above class. I've saved the class FetchingEmail.java to directory : /home/manisha/JavaMailAPIExercise. We would need the jars javax.mail.jar and activation.jar in the classpath. Execute the command below to compile the class (both the jars are placed in /home/manisha/ directory) from command prompt:

javac -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: FetchingEmail.java

Now that the class is compiled, execute the below command to run:

java -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: FetchingEmail

Verify Output

You should see the following message on the command console:

messages.length---3
---------------------------------
This is the message envelope
---------------------------
FROM: XYZ <xyz@gmail.com>
TO: ABC <abc@gmail.com>
SUBJECT: Simple Message
----------------------------
CONTENT-TYPE: multipart/alternative; boundary=047d7b343d6ad3e4ea04e8ec6579
This is a Multipart
---------------------------

----------------------------
CONTENT-TYPE: text/plain; charset=ISO-8859-1
This is plain text
---------------------------
Hi am a simple message string....

-- 
Regards
xyz

This is the message envelope
---------------------------
FROM: XYZ <xyz@gmail.com>
TO: ABC <abc@gmail.com>
SUBJECT: Attachement
----------------------------
CONTENT-TYPE: multipart/mixed; boundary=047d7b343d6a99180904e8ec6751
This is a Multipart
---------------------------

----------------------------
CONTENT-TYPE: text/plain; charset=ISO-8859-1
This is plain text
---------------------------
Hi I've an attachment.Please check

-- 
Regards
XYZ

----------------------------
CONTENT-TYPE: application/octet-stream; name=sample_attachement
This is just an input stream
---------------------------
Submit your Tutorials, White Papers and Articles into our Tutorials Directory. This is a tutorials database where we are keeping all the tutorials shared by the internet community for the benefit of others.


This is the message envelope
---------------------------
FROM: XYZ <xyz@gmail.com>
TO: ABC <abc@gmail.com>
SUBJECT: Inline Image
----------------------------
CONTENT-TYPE: multipart/related; boundary=f46d04182582be803504e8ece94b
This is a Multipart
---------------------------

----------------------------
CONTENT-TYPE: text/plain; charset=ISO-8859-1
This is plain text
---------------------------
Hi I've an inline image


[image: Inline image 3]

-- 
Regards
XYZ

----------------------------
CONTENT-TYPE: image/png; name="javamail-mini-logo.png"
content typeimage/png; name="javamail-mini-logo.png"

Here you can see there are three emails in our mailbox. First a simple mail with message "Hi am a simple message string....". The second mail has an attachment. The contents of the attachment are also printed as seen above. The third mail has an inline image.

Authentication

We will modify our CheckingMails.java from the chapter Checking Emails. Its contents are as below:

package com.howcodex;

import java.util.Properties;

import javax.mail.Authenticator;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.NoSuchProviderException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Store;

public class CheckingMails {

   public static void check(String host, String storeType, String user,
      String password) 
   {
      try {

      // create properties field
      Properties properties = new Properties();

      properties.put("mail.pop3s.host", host);
      properties.put("mail.pop3s.port", "995");
      properties.put("mail.pop3s.starttls.enable", "true");

      // Setup authentication, get session
      Session emailSession = Session.getInstance(properties,
         new javax.mail.Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
               return new PasswordAuthentication(
                  "manishapatil3may@gmail.com", "manisha123");
            }
         });
      // emailSession.setDebug(true);

      // create the POP3 store object and connect with the pop server
      Store store = emailSession.getStore("pop3s");

      store.connect();

      // create the folder object and open it
      Folder emailFolder = store.getFolder("INBOX");
      emailFolder.open(Folder.READ_ONLY);

      // retrieve the messages from the folder in an array and print it
      Message[] messages = emailFolder.getMessages();
      System.out.println("messages.length---" + messages.length);

      for (int i = 0, n = messages.length; i < n; i++) {
         Message message = messages[i];
         System.out.println("---------------------------------");
         System.out.println("Email Number " + (i + 1));
         System.out.println("Subject: " + message.getSubject());
         System.out.println("From: " + message.getFrom()[0]);
         System.out.println("Text: " + message.getContent().toString());
      }

      // close the store and folder objects
      emailFolder.close(false);
      store.close();

      } catch (NoSuchProviderException e) {
         e.printStackTrace();
      } catch (MessagingException e) {
         e.printStackTrace();
      } catch (Exception e) {
         e.printStackTrace();
      }
   }

   public static void main(String[] args) {

      String host = "pop.gmail.com";// change accordingly
      String mailStoreType = "pop3";
      String username = "abc@gmail.com";// change accordingly
      String password = "*****";// change accordingly

      check(host, mailStoreType, username, password);

   }

}

You can set the debug on by uncommenting the statement emailSession.setDebug(true);

Compile and Run

Now that our class is ready, let us compile the above class. I've saved the class CheckingMails.java to directory : /home/manisha/JavaMailAPIExercise. We would need the jars javax.mail.jar and activation.jar in the classpath. Execute the command below to compile the class (both the jars are placed in /home/manisha/ directory) from command prompt:

javac -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: CheckingMails.java

Now that the class is compiled, execute the below command to run:

java -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: CheckingMails

Verify Output

You can see a similar message as below on the command console:

messages.length---3
---------------------------------
Email Number 1
Subject: Today is a nice day
From: XYZ <xyz@gmail.com>
Text: javax.mail.internet.MimeMultipart@45f676cb
---------------------------------
Email Number 2
Subject: hiiii....
From: XYZ <xyz@gmail.com>
Text: javax.mail.internet.MimeMultipart@37f12d4f
---------------------------------
Email Number 3
Subject: helloo
From: XYZ <xyz@gmail.com>
Text: javax.mail.internet.MimeMultipart@3ad5ba3a

Replying Emails

In this chapter we will see how to reply to an email using JavaMail API. Basic steps followed in the program below are:

• Get the Session object with POP and SMTP server details in the properties. We would need POP details to retrieve messages and SMTP details to send messages.

• Create POP3 store object and connect to the store.

• Create Folder object and open the appropriate folder in your mailbox.

• Retrieve messages.

• Iterate through the messages and type "Y" or "y" if you want to reply.

• Get all information (To,From,Subject, Content) of the message.

• Build the reply message, using Message.reply() method. This method configures a new Message with the proper recipient and subject. The method takes a boolean parameter indicating whether to reply to only the sender (false) or reply to all (true).

• Set From,Text and Reply-to in the message and send it through the instance of Transport object.

• Close the Transport, folder and store objects respectively.

Here we have used JangoSMTP server via which emails are sent to our destination email address. The setup is explained in the Environment Setup chapter.

Create Java Class

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

package com.howcodex;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Date;
import java.util.Properties;

import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.Session;
import javax.mail.Store;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

public class ReplyToEmail {
   public static void main(String args[]) 
   {
      Date date = null;

      Properties properties = new Properties();
      properties.put("mail.store.protocol", "pop3");
      properties.put("mail.pop3s.host", "pop.gmail.com");
      properties.put("mail.pop3s.port", "995");
      properties.put("mail.pop3.starttls.enable", "true");
      properties.put("mail.smtp.auth", "true");
      properties.put("mail.smtp.starttls.enable", "true");
      properties.put("mail.smtp.host", "relay.jangosmtp.net");
      properties.put("mail.smtp.port", "25");
      Session session = Session.getDefaultInstance(properties);

      // session.setDebug(true);
      try 
      {
         // Get a Store object and connect to the current host
         Store store = session.getStore("pop3s");
         store.connect("pop.gmail.com", "xyz@gmail.com",
            "*****");//change the user and password accordingly

         Folder folder = store.getFolder("inbox");
         if (!folder.exists()) {
            System.out.println("inbox not found");
               System.exit(0);
         }
         folder.open(Folder.READ_ONLY);

         BufferedReader reader = new BufferedReader(new InputStreamReader(
            System.in));

         Message[] messages = folder.getMessages();
         if (messages.length != 0) {

            for (int i = 0, n = messages.length; i < n; i++) {
               Message message = messages[i];
               date = message.getSentDate();
               // 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);
               }

               System.out.print("Do you want to reply [y/n] : ");
               String ans = reader.readLine();
               if ("Y".equals(ans) || "y".equals(ans)) {

                  Message replyMessage = new MimeMessage(session);
                  replyMessage = (MimeMessage) message.reply(false);
                  replyMessage.setFrom(new InternetAddress(to));
                  replyMessage.setText("Thanks");
                  replyMessage.setReplyTo(message.getReplyTo());

                  // Send the message by authenticating the SMTP server
                  // Create a Transport instance and call the sendMessage
                  Transport t = session.getTransport("smtp");
                  try {
	   	     //connect to the SMTP server using transport instance
		     //change the user and password accordingly	
	             t.connect("abc", "****");
	             t.sendMessage(replyMessage,
                        replyMessage.getAllRecipients());
                  } finally {
                     t.close();
                  }
                  System.out.println("message replied successfully ....");

                  // close the store and folder objects
                  folder.close(false);
                  store.close();

               } else if ("n".equals(ans)) {
                  break;
               }
            }//end of for loop

         } else {
            System.out.println("There is no msg....");
         }

      } catch (Exception e) {
         e.printStackTrace();
      }

   }

}

You can set the debug on by uncommenting the statement session.setDebug(true);

Compile and Run

Now that our class is ready, let us compile the above class. I've saved the class ReplyToEmail.java to directory : /home/manisha/JavaMailAPIExercise. We would need the jars javax.mail.jar and activation.jar in the classpath. Execute the command below to compile the class (both the jars are placed in /home/manisha/ directory) from command prompt:

javac -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: ReplyToEmail.java

Now that the class is compiled, execute the following command to run:

java -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: ReplyToEmail

Verify Output

You should see the following message on the command console:

From: ABC <abc@gmail.com>
Reply-to: abc@trioteksolutions.com
To: XYZ <xyz@gmail.com>
Subject: Hi today is a nice day
Sent: Thu Oct 17 15:58:37 IST 2013
Do you want to reply [y/n] : y
message replied successfully ....

Check the inbox to which the mail was sent. In our case the message received looks as below:

Forwarding Emails

In this chapter we will see how to forward an email using JavaMail API. Basic steps followed in the program below are:

• Get the Session object with POP and SMTP server details in the properties. We would need POP details to retrieve messages and SMTP details to send messages.

• Create POP3 store object and connect to the store.

• Create Folder object and open the appropriate folder in your mailbox.

• Retrieve messages.

• Iterate through the messages and type "Y" or "y" if you want to forward.

• Get all information (To,From,Subject, Content) of the message.

• Build the forward message by working with the parts that make up a message. First part would be the text of the message and a second part would be the message to forward. Combine the two into a multipart. Then you add the multipart to a properly addressed message and send it.

• Close the Transport, folder and store objects respectively.

Here we have used JangoSMTP server via which emails are sent to our destination email address. The setup is explained in the Environment Setup chapter.

Create Java Class

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

package com.howcodex;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Date;
import java.util.Properties;

import javax.mail.BodyPart;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.Multipart;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Store;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;

public class ForwardEmail {

   public static void main(String[] args) {
      Properties properties = new Properties();
      properties.put("mail.store.protocol", "pop3");
      properties.put("mail.pop3s.host", "pop.gmail.com");
      properties.put("mail.pop3s.port", "995");
      properties.put("mail.pop3.starttls.enable", "true");
      properties.put("mail.smtp.auth", "true");
      properties.put("mail.smtp.host", "relay.jangosmtp.net");
      properties.put("mail.smtp.port", "25");
      Session session = Session.getDefaultInstance(properties);
      try {
         // session.setDebug(true);
         // Get a Store object and connect to the current host
         Store store = session.getStore("pop3s");
         store.connect("pop.gmail.com", "xyz@gmail.com",
            "*****");//change the user and password accordingly

         // Create a Folder object and open the folder
         Folder folder = store.getFolder("inbox");
         folder.open(Folder.READ_ONLY);
         BufferedReader reader = new BufferedReader(new InputStreamReader(
            System.in));
         Message[] messages = folder.getMessages();
         if (messages.length != 0) {

         for (int i = 0, n = messages.length; i < n; i++) {
            Message message = messages[i];
            // 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);
            }
            System.out.print("Do you want to reply [y/n] : ");
            String ans = reader.readLine();
            if ("Y".equals(ans) || "y".equals(ans)) {
               Message forward = new MimeMessage(session);
               // Fill in header
               forward.setRecipients(Message.RecipientType.TO,
               InternetAddress.parse(from));
               forward.setSubject("Fwd: " + message.getSubject());
               forward.setFrom(new InternetAddress(to));

               // Create the message part
               MimeBodyPart messageBodyPart = new MimeBodyPart();
               // Create a multipart message
               Multipart multipart = new MimeMultipart();
               // set content
               messageBodyPart.setContent(message, "message/rfc822");
               // Add part to multi part
               multipart.addBodyPart(messageBodyPart);
               // Associate multi-part with message
               forward.setContent(multipart);
               forward.saveChanges();

               // Send the message by authenticating the SMTP server
               // Create a Transport instance and call the sendMessage
               Transport t = session.getTransport("smtp");
               try {
                  //connect to the SMTP server using transport instance
		  //change the user and password accordingly
                  t.connect("abc", "*****");
                  t.sendMessage(forward, forward.getAllRecipients());
               } finally {
                  t.close();
               }

               System.out.println("message forwarded successfully....");

            // close the store and folder objects
            folder.close(false);
            store.close();
            }// end if

         }// end for
   }// end if
   } catch (Exception e) {
      e.printStackTrace();
   }
}

}

You can set the debug on by uncommenting the statement session.setDebug(true);

Compile and Run

Now that our class is ready, let us compile the above class. I've saved the class ForwardEmail.java to directory : /home/manisha/JavaMailAPIExercise. We would need the jars javax.mail.jar and activation.jar in the classpath. Execute the command below to compile the class (both the jars are placed in /home/manisha/ directory) from command prompt:

javac -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: ForwardEmail.java

Now that the class is compiled, execute the following command to run:

java -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: ForwardEmail

Verify Output

You should see the following message on the command console:

From: ABC <abc@gmail.com>
Reply-to: abc@trioteksolutions.com
To: XYZ <xyz@gmail.com>
Subject: Hi today is a nice day
Sent: Thu Oct 17 15:58:37 IST 2013
Do you want to reply [y/n] : y
message forwarded successfully....

Check the inbox to which the mail was sent. In our case the forwarded message would look as below:

Deleting Emails

In this chapter we will see how to delete an email using JavaMail API. Deleting messages involves working with the Flags associated with the messages. There are different flags for different states, some system-defined and some user-defined. The predefined flags are defined in the inner class Flags.Flag and are listed below:

• Flags.Flag.ANSWERED

• Flags.Flag.DELETED

• Flags.Flag.DRAFT

• Flags.Flag.FLAGGED

• Flags.Flag.RECENT

• Flags.Flag.SEEN

• Flags.Flag.USER

POP protocol supports only deleting of the messages.

Basic steps followed in the delete program are:

• Get the Session object with POP and SMTP server details in the properties. We would need POP details to retrieve messages and SMTP details to send messages.

• Create POP3 store object and connect to the store.

• Create Folder object and open the appropriate folder in your mailbox in READ_WRITE mode.

• Retrieves messages from inbox folder.

• Iterate through the messages and type "Y" or "y" if you want to delete the message by invoking the method setFlag(Flags.Flag.DELETED, true) on the Message object.

• The messages marked DELETED are not actually deleted, until we call the expunge() method on the Folder object, or close the folder with expunge set to true.

• Close the store object.

Create Java Class

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

package com.howcodex;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Properties;

import javax.mail.Flags;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.NoSuchProviderException;
import javax.mail.Session;
import javax.mail.Store;

public class DeleteEmail {

   public static void delete(String pop3Host, String storeType, String user,
      String password) 
   {
      try 
      {
         // get the session object
         Properties properties = new Properties();
         properties.put("mail.store.protocol", "pop3");
         properties.put("mail.pop3s.host", pop3Host);
         properties.put("mail.pop3s.port", "995");
         properties.put("mail.pop3.starttls.enable", "true");
         Session emailSession = Session.getDefaultInstance(properties);
         // emailSession.setDebug(true);

         // create the POP3 store object and connect with the pop server
         Store store = emailSession.getStore("pop3s");

         store.connect(pop3Host, user, password);

         // create the folder object and open it
         Folder emailFolder = store.getFolder("INBOX");
         emailFolder.open(Folder.READ_WRITE);

         BufferedReader reader = new BufferedReader(new InputStreamReader(
            System.in));
         // retrieve the messages from the folder in an array and print it
         Message[] messages = emailFolder.getMessages();
         System.out.println("messages.length---" + messages.length);
         for (int i = 0; i < messages.length; i++) {
            Message message = messages[i];
            System.out.println("---------------------------------");
            System.out.println("Email Number " + (i + 1));
            System.out.println("Subject: " + message.getSubject());
            System.out.println("From: " + message.getFrom()[0]);

            String subject = message.getSubject();
            System.out.print("Do you want to delete this message [y/n] ? ");
            String ans = reader.readLine();
            if ("Y".equals(ans) || "y".equals(ans)) {
	       // set the DELETE flag to true
	       message.setFlag(Flags.Flag.DELETED, true);
	       System.out.println("Marked DELETE for message: " + subject);
            } else if ("n".equals(ans)) {
	       break;
            }
         }
         // expunges the folder to remove messages which are marked deleted
         emailFolder.close(true);
         store.close();

      } catch (NoSuchProviderException e) {
         e.printStackTrace();
      } catch (MessagingException e) {
         e.printStackTrace();
      } catch (IOException io) {
         io.printStackTrace();
      }
   }

   public static void main(String[] args) {

      String host = "pop.gmail.com";// change accordingly
      String mailStoreType = "pop3";
      String username = "abc@gmail.com";// change accordingly
      String password = "*****";// change accordingly

      delete(host, mailStoreType, username, password);

   }

}

You can set the debug on by uncommenting the statement emailSession.setDebug(true);

Compile and Run

Now that our class is ready, let us compile the above class. I've saved the class DeleteEmail.java to directory : /home/manisha/JavaMailAPIExercise. We would need the jars javax.mail.jar and activation.jar in the classpath. Execute the command below to compile the class (both the jars are placed in /home/manisha/ directory) from command prompt:

javac -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: DeleteEmail.java

Now that the class is compiled, execute the following command to run:

java -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: DeleteEmail

Verify Output

You should see the following message on the command console:

messages.length---1
---------------------------------
Email Number 1
Subject: Testing
From: ABC <abc@gmail.com>
Do you want to delete this message [y/n] ? y
Marked DELETE for message: Testing

Gmail SMTP Server

In all previous chapters we used JangoSMTP server to send emails. In this chapter we will learn about SMTP server provided by Gmail. Gmail (among others) offers use of their public SMTP server free of charge.

Gmail SMTP server details can be found here. As you can see in the details, we can use either TLS or SSL connection to send email via Gmail SMTP server.

The procedure to send email using Gmail SMTP server is similar as explained in chapter Sending Emails, except that we would change the host server. As a pre-requisite the sender email address should be an active gmail account. Let us try an example.

Create Java Class

Create a Java file SendEmailUsingGMailSMTP, contents of which are as below:

package com.howcodex;

import java.util.Properties;

import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

public class SendEmailUsingGMailSMTP {
   public static void main(String[] args) {
      // Recipient's email ID needs to be mentioned.
      String to = "xyz@gmail.com";//change accordingly

      // Sender's email ID needs to be mentioned
      String from = "abc@gmail.com";//change accordingly
      final String username = "abc";//change accordingly
      final String password = "*****";//change accordingly

      // Assuming you are sending email through relay.jangosmtp.net
      String host = "smtp.gmail.com";

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

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

      try {
         // Create a default MimeMessage object.
         Message message = new MimeMessage(session);

         // Set From: header field of the header.
         message.setFrom(new InternetAddress(from));

         // Set To: header field of the header.
         message.setRecipients(Message.RecipientType.TO,
         InternetAddress.parse(to));

         // Set Subject: header field
         message.setSubject("Testing Subject");

         // Now set the actual message
         message.setText("Hello, this is sample for to check send "
            + "email using JavaMailAPI ");

         // Send message
         Transport.send(message);

         System.out.println("Sent message successfully....");

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

Here the host is set as smtp.gmail.com and port is set as 587. Here we have enabled TLS connection.

Compile and Run

Now that our class is ready, let us compile the above class. I've saved the class SendEmailUsingGMailSMTP.java to directory : /home/manisha/JavaMailAPIExercise. We would need the jars javax.mail.jar and activation.jar in the classpath. Execute the command below to compile the class (both the jars are placed in /home/manisha/ directory) from command prompt:

javac -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: SendEmailUsingGMailSMTP.java

Now that the class is compiled, execute the below command to run:

java -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: SendEmailUsingGMailSMTP

Verify Output

You should see the following message on the command console:

Sent message successfully....

Folder Management

So far, we’ve worked in our previous chapters mostly with the INBOX folder. This is the default folder in which most mail resides. Some systems might call it as INBOX and some other might call it by some other name. But,you can always access it from the JavaMail API using the name INBOX.

The JavaMail API represents folders as instances of the abstract Folder class:

public abstract class Folder extends Object

This class declares methods for requesting named folders from servers, deleting messages from folders, searching for particular messages in folders, listing the messages in a folder, and so forth.

Opening a Folder

We can't create a folder directly as the only constructor in the Folder class is protected. We can get a Folder from:

• a Session

• a Store

• or another Folder

All the above classes have a similar getFolder() method with similar signature:

public abstract Folder getFolder(String name) throws MessagingException

Some of the methods which help in getting the Folder object are:

Basic Folder Info

Following are some of the methods in Folder class which return basic information about a folder:

Managing Folder

Following are some of the methods which help manage the Folder:

Managing Messages in Folders

Following are some of the methods that help manage the messages in Folder:

Listing the Contents of a Folder

There are four methods to list the folders that a folder contains:

Checking for Mail

Getting Messages from Folders

The Folder class provides four methods for retrieving messages from open folders:

Searching Folders

If the server supports searching (as many IMAP servers do and most POP servers don’t), it’s easy to search a folder for the messages meeting certain criteria. The criteria are encoded in SearchTerm objects. Following are the two search methods:

Flags

Flag modification is useful when you need to change flags for the entire set of messages in a Folder. Following are the methods provided in the Folder class:

Quota Management

A quota in JavaMail is a limited or fixed number or amount of messages in a email store. Each Mail service request counts toward the JavaMail API Calls quota. An email service can apply following quota criterion:

• Maximum size of outgoing mail messages, including attachments.

• Maximum size of incoming mail messages, including attachments.

• Maximum size of message when an administrator is a recipient

For Quota management JavaMail has following classes:

Let us see and example in the following sections which checks for mail storage name, limit and its usage.

Create Java Class

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

package com.howcodex;

import java.util.Properties;

import javax.mail.Quota;
import javax.mail.Session;
import javax.mail.Store;

import com.sun.mail.imap.IMAPStore;

public class QuotaExample 
{
   public static void main(String[] args) 
   {
      try 
      {
         Properties properties = new Properties();
         properties.put("mail.store.protocol", "imaps");
         properties.put("mail.imaps.port", "993");
         properties.put("mail.imaps.starttls.enable", "true");
         Session emailSession = Session.getDefaultInstance(properties);
         // emailSession.setDebug(true);

         // create the IMAP3 store object and connect with the pop server
         Store store = emailSession.getStore("imaps");

         //change the user and password accordingly
         store.connect("imap.gmail.com", "abc@gmail.com", "*****");
         IMAPStore imapStore = (IMAPStore) store;
         System.out.println("imapStore ---" + imapStore);

         //get quota
         Quota[] quotas = imapStore.getQuota("INBOX");
         //Iterate through the Quotas
         for (Quota quota : quotas) {
            System.out.println(String.format("quotaRoot:'%s'",
               quota.quotaRoot));
            //Iterate through the Quota Resource
            for (Quota.Resource resource : quota.resources) {
               System.out.println(String.format(
                  "name:'%s', limit:'%s', usage:'%s'", resource.name,
                  resource.limit, resource.usage));
            }
         }
      } catch (Exception e) 
      {
         e.printStackTrace();
      }
   }
}

Here are connection to the gmail service via IMAP (imap.gmail.com) server, as IMAPStore implements the QuotaAwareStore. Once you get the Store object, fetch the Quota array and iterate through it and print the relevant information.

Compile and Run

Now that our class is ready, let us compile the above class. I've saved the class QuotaExample.java to directory : /home/manisha/JavaMailAPIExercise. We would need the jars javax.mail.jar and activation.jar in the classpath. Execute the command below to compile the class (both the jars are placed in /home/manisha/ directory) from command prompt:

javac -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: QuotaExample.java

Now that the class is compiled, execute the below command to run:

java -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: QuotaExample

Verify Output

You should see a similar message on the command console:

imapStore ---imaps://abc%40gmail.com@imap.gmail.com
quotaRoot:''
name:'STORAGE', limit:'15728640', usage:'513'

Bounced Messages

A message can be bounced for several reasons. This problem is discussed in depth at rfc1211. Only a server can determine the existence of a particular mailbox or user name. When the server detects an error, it will return a message indicating the reason for the failure to the sender of the original message.

There are many Internet standards covering Delivery Status Notifications but a large number of servers don't support these new standards, instead using ad hoc techniques for returning such failure messages. Hence it get very difficult to correlate the bounced message with the original message that caused the problem.

JavaMail includes support for parsing Delivery Status Notifications. There are a number of techniques and heuristics for dealing with this problem. One of the techniques being Variable Envelope Return Paths. You can set the return path in the enveloper as shown in the example below. This is the address where bounce mails are sent to. You may want to set this to a generic address, different than the From: header, so you can process remote bounces. This done by setting mail.smtp.from property in JavaMail.

Create Java Class

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

import java.util.Properties;

import javax.mail.Message;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

public class SendEmail {
   public static void main(String[] args) throws Exception {
      String smtpServer = "smtp.gmail.com";
      int port = 587;
      final String userid = "youraddress";//change accordingly
      final String password = "*****";//change accordingly
      String contentType = "text/html";
      String subject = "test: bounce an email to a different address " +
				"from the sender";
      String from = "youraddress@gmail.com";
      String to = "bouncer@fauxmail.com";//some invalid address
      String bounceAddr = "toaddress@gmail.com";//change accordingly
      String body = "Test: get message to bounce to a separate email address";

      Properties props = new Properties();

      props.put("mail.smtp.auth", "true");
      props.put("mail.smtp.starttls.enable", "true");
      props.put("mail.smtp.host", smtpServer);
      props.put("mail.smtp.port", "587");
      props.put("mail.transport.protocol", "smtp");
      props.put("mail.smtp.from", bounceAddr);

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

      MimeMessage message = new MimeMessage(mailSession);
      message.addFrom(InternetAddress.parse(from));
      message.setRecipients(Message.RecipientType.TO, to);
      message.setSubject(subject);
      message.setContent(body, contentType);

      Transport transport = mailSession.getTransport();
      try {
         System.out.println("Sending ....");
         transport.connect(smtpServer, port, userid, password);
         transport.sendMessage(message,
            message.getRecipients(Message.RecipientType.TO));
         System.out.println("Sending done ...");
      } catch (Exception e) {
         System.err.println("Error Sending: ");
         e.printStackTrace();

      }
      transport.close();
   }// end function main()
}

Here we can see that the property mail.smtp.from is set different from the from address.

Compile and Run

Now that our class is ready, let us compile the above class. I've saved the class SendEmail.java to directory : /home/manisha/JavaMailAPIExercise. We would need the jars javax.mail.jar and activation.jar in the classpath. Execute the command below to compile the class (both the jars are placed in /home/manisha/ directory) from command prompt:

javac -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: SendEmail.java

Now that the class is compiled, execute the below command to run:

java -cp /home/manisha/activation.jar:/home/manisha/javax.mail.jar: SendEmail

Verify Output

You should see the following message on the command console:

Sending ....
Sending done ...

SMTP Servers

SMTP is an acronym for Simple Mail Transfer Protocol. It is an Internet standard for electronic mail (e-mail) transmission across Internet Protocol (IP) networks. SMTP uses TCP port 25. SMTP connections secured by SSL are known by the shorthand SMTPS, though SMTPS is not a protocol in its own right.

JavaMail API has package com.sun.mail.smtp which act as SMTP protocol provider to access an SMTP server. Following table lists the classes included in this package:

The following table lists the exceptions thrown:

The com.sun.mail.smtp provider use SMTP Authentication optionally. To use SMTP authentication you'll need to set the mail.smtp.auth property or provide the SMTP Transport with a username and password when connecting to the SMTP server. You can do this using one of the following approaches:

• Provide an Authenticator object when creating your mail Session and provide the username and password information during the Authenticator callback. mail.smtp.user property can be set to provide a default username for the callback, but the password will still need to be supplied explicitly. This approach allows you to use the static Transport send method to send messages. For example:

Transport.send(message);

Transport tr = session.getTransport("smtp");
tr.connect(smtphost, username, password);
msg.saveChanges();
tr.sendMessage(msg, msg.getAllRecipients());
tr.close();

The SMTP protocol provider supports the following properties, which may be set in the JavaMail Session object. The properties are always set as strings. For example:

 props.put("mail.smtp.port", "587");

IMAP Servers

IMAP is Acronym for Internet Message Access Protocol. It is an Application Layer Internet protocol that allows an e-mail client to access e-mail on a remote mail server. An IMAP server typically listens on well-known port 143. IMAP over SSL (IMAPS) is assigned to port number 993.

IMAP supports both on-line and off-line modes of operation. E-mail clients using IMAP generally leave messages on the server until the user explicitly deletes them.

Package com.sun.mail.imap is an IMAP protocol provider for the JavaMail API that provides access to an IMAP message store. The table below lists the interface and classes of this provider:

Some points to be noted above this provider:

• This provider supports both the IMAP4 and IMAP4rev1 protocols.

• A connected IMAPStore maintains a pool of IMAP protocol objects for use in communicating with the IMAP server. As folders are opened and new IMAP protocol objects are needed, the IMAPStore will provide them from the connection pool, or create them if none are available. When a folder is closed, its IMAP protocol object is returned to the connection pool if the pool .

• The connected IMAPStore object may or may not maintain a separate IMAP protocol object that provides the store a dedicated connection to the IMAP server.

POP3 Servers

Post Office Protocol (POP) is an application-layer Internet standard protocol used by local e-mail clients to retrieve e-mail from a remote server over a TCP/IP connection. POP supports simple download-and-delete requirements for access to remote mailboxes. A POP3 server listens on well-known port 110.

Package com.sun.mail.pop3 is a POP3 protocol provider for the JavaMail API that provides access to a POP3 message store. The table below lists the classes in this package:

Some points to be noted above this provider:

• POP3 provider supports only a single folder named INBOX. Due to the limitations of the POP3 protocol, many of the JavaMail API capabilities like event notification, folder management, flag management, etc. are not allowed.

• The POP3 provider is accessed through the JavaMail APIs by using the protocol name pop3 or a URL of the form pop3://user:password@host:port/INBOX".

• POP3 supports no permanent flags. For example the Flags.Flag.RECENT flag will never be set for POP3 messages. It's up to the application to determine which messages in a POP3 mailbox are new.

• POP3 does not support the Folder.expunge() method. To delete and expunge messages, set the Flags.Flag.DELETED flag on the messages and close the folder using the Folder.close(true) method.

• POP3 does not provide a received date, so the getReceivedDate method will return null.

• When the headers of a POP3 message are accessed, the POP3 provider uses the TOP command to fetch all headers, which are then cached.

• When the content of a POP3 message is accessed, the POP3 provider uses the RETR command to fetch the entire message.

• The POP3Message.invalidate method can be used to invalidate cached data without closing the folder.