Sending Mail Using JavaMail API and Gmail as SMTP server

The JavaMail API provides a platform-independent and protocol-independent framework to build mail and messaging applications. The API defines classes such as Message, Session, and Transport. It includes support for the IMAP4, POP3, and SMTP protocols. Here I am going to show you how you can use this API to send mail through SMTP protocol.

First create a MailUtility class which you can use later from your client code.

public class MailUtility {

//Set Gmail as SMTP host 
private String SMTP_HOST_NAME = "smtp.gmail.com";
private String SMTP_AUTH_USER = "yourgmailid@gmail.com";
private String SMTP_AUTH_PWD = "password";

public void postMail(String recipients[], String subject,
String message, String from) throws MessagingException {
boolean debug = false;

//Set the required JavaMail session properties
Properties props = new Properties();
props.put("mail.smtp.starttls.enable", "true");
props.put("mail.smtp.host", SMTP_HOST_NAME);
props.put("mail.smtp.user", SMTP_AUTH_USER);
props.put("mail.smtp.password", SMTP_AUTH_PWD);
props.put("mail.smtp.auth", "true");
props.put("mail.smtp.port", "465");
props.put("mail.smtp.ssl", "true");

props.put("mail.smtp.socketFactory.port", "465");
props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
props.put("mail.smtp.socketFactory.fallback", "false");

//Create an Authenticator. You will find the SMTPAuthenticator class defination later
Authenticator auth = new SMTPAuthenticator();

//Create a Session from the Properties and the Authenticator
Session session = Session.getInstance(props, auth);
session.setDebug(debug);

// Create a MimeMessage
MimeMessage msg = new MimeMessage(session);

// Set the from and to address
InternetAddress addressFrom = new InternetAddress(from);
msg.setFrom(addressFrom);

InternetAddress[] addressTo = new InternetAddress[recipients.length];
for (int i = 0; i < recipients.length; i++) {
addressTo[i] = new InternetAddress(recipients[i]);
}
msg.setRecipients(Message.RecipientType.TO, addressTo);

//Set message subject and text
msg.setSubject(subject);
msg.setText(message);

//Finally now send the message.
try {
Transport.send(msg);
} catch (MessagingException messagingException) {
messagingException.printStackTrace();
} catch (Exception ex) {
ex.printStackTrace();
}

}

//SimpleAuthenticator is used to do simple authentication
//when the SMTP server requires it.

private class SMTPAuthenticator extends javax.mail.Authenticator {

@Override
public PasswordAuthentication getPasswordAuthentication() {
String username = SMTP_AUTH_USER;
String password = SMTP_AUTH_PWD;
return new PasswordAuthentication(username, password);
}
}
}

And here is the client code that uses the MailUtility class for sending mail.

String emailMsgTxt = "Hello, this is a test mail from my mail application.\n";
String emailSubjectTxt = "Test Mail";
String emailFromAddress = "yourgmailid@gmail.com";
String[] receipentList=
 {
      "abc@gmail.com",
      "wxx@yahoo.com"
 };
try
{
      MailUtility smtpMailSender = new MailUtility();
      smtpMailSender.postMail(receipentList, emailSubjectTxt, emailMsgTxt, emailFromAddress);
} catch (MessagingException messagingException)
{
      messagingException.printStackTrace();
} catch (Exception ex)
{
     ex.printStackTrace();
}

That's all. Another day I will describe how you can send mail asynchronously using this mail API.