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Getting Started With Creating A Java Email Client

This tutorial is largely copied from tutorialspoint's Java - Sending Email, I am just updating it to keep it relevant.

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.

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.

Send a Simple E-mail

Here is an example to send a simple e-mail from your machine. Here it is assumed that your localhost is connected to the internet and capable enough to send an email.

// File Name SendEmail.java

import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;

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

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

        // Assuming you are sending email from localhost
        String host = "localhost";

        // Get system properties
        Properties properties = System.getProperties();

        // Setup mail server
        properties.setProperty("mail.smtp.host", host);

        // Get the default Session object.
        Session session = Session.getDefaultInstance(properties);

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

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

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

            // Set Subject: header field
            message.setSubject("This is the Subject Line!");

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

            // Send message
            Transport.send(message);
            System.out.println("Sent message successfully....");
        }
        catch (MessagingException mex) 
        {
            mex.printStackTrace();
        }
    }
}

Compile and run this program to send a simple e-mail:

java SendEmail
Sent message successfully....

If you want to send an e-mail to multiple recipients then following methods would be used to specify multiple e-mail IDs:

void addRecipients(Message.RecipientType type, Address[] addresses)throws MessagingException

Here is the description of the parameters:

  • type: This would be set to TO, CC or BCC. Here CC represents Carbon Copy and BCC represents Black Carbon Copy. Example Message.RecipientType.TO

  • addresses: This is the array of email ID. You would need to use InternetAddress() method while specifying email IDs

Send an HTML E-mail:

Here is an example to send an HTML email from your machine. Here it is assumed that your localhost is connected to the internet and capable enough to send an email.

This example is very similar to previous one, except 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.

// File Name SendHTMLEmail.java

import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;

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

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

        // Assuming you are sending email from localhost
        String host = "localhost";

        // Get system properties
        Properties properties = System.getProperties();

        // Setup mail server
        properties.setProperty("mail.smtp.host", host);

        // Get the default Session object.
        Session session = Session.getDefaultInstance(properties);

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

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

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

            // Set Subject: header field
            message.setSubject("This is the Subject Line!");

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

            // Send message
            Transport.send(message);
            System.out.println("Sent message successfully....");
        }
        catch (MessagingException mex) 
        {
            mex.printStackTrace();
        }
    }
}

Compile and run this program to send an HTML e-mail:

$ java SendHTMLEmail
Sent message successfully....

Send Attachment in E-mail:

Here is an example to send an email with attachment from your machine. Here it is assumed that your localhost is connected to the internet and capable enough to send an email.

// File Name SendFileEmail.java

import java.util.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;

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

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

        // Assuming you are sending email from localhost
        String host = "localhost";

        // Get system properties
        Properties properties = System.getProperties();

        // Setup mail server
        properties.setProperty("mail.smtp.host", host);

        // Get the default Session object.
        Session session = Session.getDefaultInstance(properties);

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

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

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

            // Set Subject: header field
            message.setSubject("This is the Subject Line!");

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

            // Fill the 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 = "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 mex) 
        {
            mex.printStackTrace();
        }
    }
}

Compile and run this program to send an HTML e-mail:

java SendFileEmail
Sent message successfully....

User Authentication Part:

If it is required to provide user ID and Password to the e-mail server for authentication purpose then you can set these properties as follows:

props.setProperty("mail.user", "myuser");
props.setProperty("mail.password", "mypwd");

Rest of the e-mail sending mechanism would remain as explained above.

References

Last updated: 16th August 2018
First published: 16th August 2018