How to Send E-mail in Java?

Last Updated : 28 Mar 2025

It is a fundamental necessity to send e-mails, no matter what platform you are using-Python, JavaEE, Java, etc. It can be necessary to send e-mails to confirm registration or sign up or to issue error notices. Writing Java applications allows you to send e-mails using Java.

1. Setting Up the JavaMail API

You must configure the environment with the required dependencies before creating the code to send e-mails.

2. Sending a Simple E-mail in Java

File Name: E-mailSender.java

import javax.mail.*;
import javax.mail.internet.*;
import java.util.Properties;
public class E-mailsender {
    public static void main(String[] args) {
        // Set up e-mail server properties
        Properties propt = new Properties();
        propt.put("mail.smtp.host", "smtp.gmail.com"); 
        propt.put("mail.smtp.port", "587"); 
        propt.put("mail.smtp.auth", "true"); 
        propt.put("mail.smtp.starttls.enable", "true"); 
        // Create a session with authentication
        Session session = Session.getInstance(props, new javax.mail.Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication("your-email@gmail.com", "your-email-password");
            }
        });
        try {
            // Create the e-mail message
            Message message = new MimeMessage(session);
            message.setFrom(new InternetAddress("your-email@gmail.com"));
            message.setRecipients(
                    Message.RecipientType.TO,
                    InternetAddress.parse("recipient@example.com")
            );
            message.setSubject("Test E-mail from Java");
            message.setText("Hello, this is a test e-mail sent from Java!");
            // Send the e-mail
            Transport.send(message);
            System.out.println("E-mail sent successfully!");
        } catch (MessagingException e) {
            e.printStackTrace();
        }
    }
}   

Output:

 
E-mail sent successfully!

Explanation

Properties: We set the SMTP server properties, including the host (Gmail in this case), port (587 for TLS), and enabling TLS and authentication.
Session: This is the core object in JavaMail that manages the e-mail session. We authenticate using a valid e-mail and password.
MimeMessage: Represents the e-mail message. We set the sender, recipient, subject, and body content.
Transport.send(): This method sends the e-mail.

3. Security Considerations

Application-Specific Password

If you are using Gmail, Google might block your login attempts from this Java application for security reasons. To bypass this, create an App Password from your Google Account settings under the Security Tab. Use this password instead of your regular Gmail password in the Java code.

Handling Exceptions and Logging

Always handle exceptions such as MessagingException when working with e-mails. You can log these errors for troubleshooting purposes.

catch (MessagingException e) {
    e.printStackTrace();
    System.out.println("Error sending email: " + e.getMessage());
}   

Environment Variables for Security

For production environments, it's better to avoid hardcoding sensitive information such as email credentials. Instead, store them in environment variables or external configuration files.

4. Adding More Features

Sending HTML E-mails

You can modify the code to send HTML e-mails by using message.setContent() instead of message.setText():

message.setContent("<h1>Hello from Java</h1><p>This is an HTML email</p>", "text/html");   

Adding Attachments

To send attachments, you can use a Multipart object to combine the e-mail body and the file attachment:

MimeBodyPart messageBodyPart = new MimeBodyPart();
messageBodyPart.setText("This is the email body");
MimeBodyPart attachmentPart = new MimeBodyPart();
attachmentPart.attachFile("path/to/file");
Multipart multipart = new MimeMultipart();
multipart.addBodyPart(messageBodyPart);
multipart.addBodyPart(attachmentPart);
message.setContent(multipart);   

Conclusion

The JavaMail API is a powerful tool for sending e-mails through Java applications. With the example provided, you can send simple e-mails, but the API offers additional functionality, such as sending HTML e-mails, attachments, and even more advanced configurations.

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