[java] Send email using java

I'm trying to send an email using 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 = "[email protected]";

      // Sender's email ID needs to be mentioned
      String from = "[email protected]";

      // 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();
      }
   }
}

I am getting the error :

javax.mail.MessagingException: Could not connect to SMTP host: localhost, port: 25;
  nested exception is:java.net.ConnectException: Connection refused: connect
        at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1706)
        at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:525)

Will this code work to send email?

This question is related to java email

The answer is


Here is the working solution bro. It's guranteed.

  1. First of all open your gmail account from which you wanted to send mail, like in you case [email protected]
  2. Open this link below:

    https://support.google.com/accounts/answer/6010255?hl=en

  3. Click on "Go to the "Less secure apps" section in My Account." option
  4. Then turn on it
  5. That's it (:

Here is my code:

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

public class SendEmail {

   final String senderEmailID = "Sender Email id";
final String senderPassword = "Sender Pass word";
final String emailSMTPserver = "smtp.gmail.com";
final String emailServerPort = "465";
String receiverEmailID = null;
static String emailSubject = "Test Mail";
static String emailBody = ":)";
public SendEmail(String receiverEmailID, String emailSubject, String emailBody)
{
this.receiverEmailID=receiverEmailID;
this.emailSubject=emailSubject;
this.emailBody=emailBody;
Properties props = new Properties();
props.put("mail.smtp.user",senderEmailID);
props.put("mail.smtp.host", emailSMTPserver);
props.put("mail.smtp.port", emailServerPort);
props.put("mail.smtp.starttls.enable", "true");
props.put("mail.smtp.auth", "true");
props.put("mail.smtp.socketFactory.port", emailServerPort);
props.put("mail.smtp.socketFactory.class","javax.net.ssl.SSLSocketFactory");
props.put("mail.smtp.socketFactory.fallback", "false");
SecurityManager security = System.getSecurityManager();
try
{
Authenticator auth = new SMTPAuthenticator();
Session session = Session.getInstance(props, auth);
MimeMessage msg = new MimeMessage(session);
msg.setText(emailBody);
msg.setSubject(emailSubject);
msg.setFrom(new InternetAddress(senderEmailID));
msg.addRecipient(Message.RecipientType.TO,
new InternetAddress(receiverEmailID));
Transport.send(msg);
System.out.println("Message send Successfully:)");
}
catch (Exception mex)
{
mex.printStackTrace();
}
}
public class SMTPAuthenticator extends javax.mail.Authenticator
{
public PasswordAuthentication getPasswordAuthentication()
{
return new PasswordAuthentication(senderEmailID, senderPassword);
}
}
    public static void main(String[] args) {
       SendEmail mailSender;
        mailSender = new SendEmail("Receiver Email id","Testing Code 2 example","Testing Code Body yess");
    }

}

I got the same exception as you got. Reason for this is not having up and running smpt server in your machine(since your host is localhost). If you use windows 7 it does not have SMTP server . so you will have to download, install and configure with domain and creating accounts.I used hmailserver as smtp server installed and configure in my local machine. https://www.hmailserver.com/download


Following code worked for me.

import java.io.UnsupportedEncodingException;
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.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;


public class SendMail {

    public static void main(String[] args) {

        final String username = "[email protected]";
        final String password = "yourpassword";

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

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

        try {

            Message message = new MimeMessage(session);
            message.setFrom(new InternetAddress("[email protected]"));
            message.setRecipients(Message.RecipientType.TO,
                InternetAddress.parse("[email protected]"));
            message.setSubject("Testing Subject");
            message.setText("Dear Mail Crawler,"
                + "\n\n No spam to my email, please!");

            Transport.send(message);

            System.out.println("Done");

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

It has been quite a while since this has been posted. But as of Nov 13, 2012 I can verify that port 465 still works.

Refer to GaryM's answer on this forum. I hope this helps few more people.

/*
* Created on Feb 21, 2005
*
*/

import java.security.Security;
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 GoogleTest {

    private static final String SMTP_HOST_NAME = "smtp.gmail.com";
    private static final String SMTP_PORT = "465";
    private static final String emailMsgTxt = "Test Message Contents";
    private static final String emailSubjectTxt = "A test from gmail";
    private static final String emailFromAddress = "";
    private static final String SSL_FACTORY = "javax.net.ssl.SSLSocketFactory";
    private static final String[] sendTo = { "" };


    public static void main(String args[]) throws Exception {

        Security.addProvider(new com.sun.net.ssl.internal.ssl.Provider());

        new GoogleTest().sendSSLMessage(sendTo, emailSubjectTxt,
            emailMsgTxt, emailFromAddress);
        System.out.println("Sucessfully mail to All Users");
    }

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

        Properties props = new Properties();
        props.put("mail.smtp.host", SMTP_HOST_NAME);
        props.put("mail.smtp.auth", "true");
        props.put("mail.debug", "true");
        props.put("mail.smtp.port", SMTP_PORT);
        props.put("mail.smtp.socketFactory.port", SMTP_PORT);
        props.put("mail.smtp.socketFactory.class", SSL_FACTORY);
        props.put("mail.smtp.socketFactory.fallback", "false");

        Session session = Session.getDefaultInstance(props,
            new javax.mail.Authenticator() {
                protected PasswordAuthentication getPasswordAuthentication() {
                    return new PasswordAuthentication("xxxxxx", "xxxxxx");
            }
        });

        session.setDebug(debug);

        Message msg = new MimeMessage(session);
        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);
        }
        msg.setRecipients(Message.RecipientType.TO, addressTo);

        // Setting the Subject and Content Type
        msg.setSubject(subject);
        msg.setContent(message, "text/plain");
        Transport.send(msg);
    }
}

Try this out. it works well for me. Make sure that before send email u need to give the access for less secure app in your gmail account. So go to the following link and try out with this java code.
Activate gmail for less secure app

You need to import javax.mail.jar file and activation.jar file to your project.

This is the full code for send email in java

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

public class SendEmail {

    final String senderEmail = "your email address";
    final String senderPassword = "your password";
    final String emailSMTPserver = "smtp.gmail.com";
    final String emailServerPort = "587";
    String receiverEmail = null;
    String emailSubject = null;
    String emailBody = null;

    public SendEmail(String receiverEmail, String Subject, String message) {
        this.receiverEmail = receiverEmail;
        this.emailSubject = Subject;
        this.emailBody = message;

        Properties props = new Properties();
        props.put("mail.smtp.user", senderEmail);
        props.put("mail.smtp.host", emailSMTPserver);
        props.put("mail.smtp.port", emailServerPort);
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.socketFactory.port", emailServerPort);
        props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");

        SecurityManager security = System.getSecurityManager();

        try {
            Authenticator auth = new SMTPAuthenticator();
            Session session = Session.getInstance(props, auth);

            Message msg = new MimeMessage(session);
            msg.setText(emailBody);
            msg.setSubject(emailSubject);
            msg.setFrom(new InternetAddress(senderEmail));
            msg.addRecipient(Message.RecipientType.TO,
                    new InternetAddress(receiverEmail));
            Transport.send(msg);
            System.out.println("send successfully");
        } catch (Exception ex) {
            System.err.println("Error occurred while sending.!");
        }

    }

    private class SMTPAuthenticator extends javax.mail.Authenticator {

        public PasswordAuthentication getPasswordAuthentication() {
            return new PasswordAuthentication(senderEmail, senderPassword);
        }
    }

    public static void main(String[] args) {
        SendEmail send = new SendEmail("receiver email address", "subject", "message");
    }

}

I have put my working gmail java class up on pastebin for your review, pay special attention to the "startSessionWithTLS" method and you may be able adjust JavaMail to provide the same functionality. http://pastebin.com/VE8Mqkqp


Will this code work to send email?

Well, no, not without changing some parts since you're getting an error. You are currently trying to send mail via a SMTP server running on localhost but you aren't running any hence the ConnectException.

Assuming the code is OK (I didn't really check), you'll have to either run a local SMTP server, or to use a (remote) one (from your ISP).

Regarding the code, you can find samples in the JavaMail download package as mentioned in the FAQ:

Where can I find some example programs that show how to use JavaMail?

Q: Where can I find some example programs that show how to use JavaMail?
A: There are many example programs included in the JavaMail download package, including simple command line programs illustrating various aspects of the JavaMail API, a Swing-based GUI application, a simple servlet-based application, and a complete web application using JSP pages and a tag library.


The following code works very well.Try this as a java application with javamail-1.4.5.jar

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

public class MailSender
{
    final String senderEmailID = "[email protected]";
    final String senderPassword = "typesenderpassword";
    final String emailSMTPserver = "smtp.gmail.com";
    final String emailServerPort = "465";
    String receiverEmailID = null;
    static String emailSubject = "Test Mail";
    static String emailBody = ":)";

    public MailSender(
            String receiverEmailID,
            String emailSubject,
            String emailBody
    ) {
        this.receiverEmailID=receiverEmailID;
        this.emailSubject=emailSubject;
        this.emailBody=emailBody;
        Properties props = new Properties();
        props.put("mail.smtp.user",senderEmailID);
        props.put("mail.smtp.host", emailSMTPserver);
        props.put("mail.smtp.port", emailServerPort);
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.socketFactory.port", emailServerPort);
        props.put("mail.smtp.socketFactory.class","javax.net.ssl.SSLSocketFactory");
        props.put("mail.smtp.socketFactory.fallback", "false");
        SecurityManager security = System.getSecurityManager();
        try {
            Authenticator auth = new SMTPAuthenticator();
            Session session = Session.getInstance(props, auth);
            MimeMessage msg = new MimeMessage(session);
            msg.setText(emailBody);
            msg.setSubject(emailSubject);
            msg.setFrom(new InternetAddress(senderEmailID));
            msg.addRecipient(Message.RecipientType.TO,
                    new InternetAddress(receiverEmailID));
            Transport.send(msg);
            System.out.println("Message send Successfully:)");
        }
        catch (Exception mex)
        {
            mex.printStackTrace();
        }
    }

    public class SMTPAuthenticator extends javax.mail.Authenticator
    {
        public PasswordAuthentication getPasswordAuthentication()
        {
            return new PasswordAuthentication(senderEmailID, senderPassword);
        }
    }

    public static void main(String[] args)
    {
        MailSender mailSender=new
            MailSender("[email protected]",emailSubject,emailBody);
    }
}

import java.util.Date;
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 extends Object{

public static void main(String [] args)
{

    try{

        Properties props = new Properties();
        props.put("mail.smtp.host", "smtp.mail.yahoo.com"); // for gmail use smtp.gmail.com
        props.put("mail.smtp.auth", "true");
        props.put("mail.debug", "true"); 
        props.put("mail.smtp.starttls.enable", "true");
        props.put("mail.smtp.port", "465");
        props.put("mail.smtp.socketFactory.port", "465");
        props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
        props.put("mail.smtp.socketFactory.fallback", "false");

        Session mailSession = Session.getInstance(props, new javax.mail.Authenticator() {

            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication("[email protected]", "password");
            }
        });

        mailSession.setDebug(true); // Enable the debug mode

        Message msg = new MimeMessage( mailSession );

        //--[ Set the FROM, TO, DATE and SUBJECT fields
        msg.setFrom( new InternetAddress( "[email protected]" ) );
        msg.setRecipients( Message.RecipientType.TO,InternetAddress.parse("[email protected]") );
        msg.setSentDate( new Date());
        msg.setSubject( "Hello World!" );

        //--[ Create the body of the mail
        msg.setText( "Hello from my first e-mail sent with JavaMail" );

        //--[ Ask the Transport class to send our mail message
        Transport.send( msg );

    }catch(Exception E){
        System.out.println( "Oops something has gone pearshaped!");
        System.out.println( E );
    }
}
}

Required jar files

Click here - How to add External Jars


The short answer - No.

The long answer - no, since the code relies on the presence of a SMTP server running on the local machine, and listening on port 25. The SMTP server (technically the MTA or Mail Transfer Agent) is responsible for communicating with the Mail User Agent (MUA, which in this case is the Java process) to receive outgoing emails.

Now, MTAs are typically responsible for receiving mails from users for a particular domain. So, for the domain gmail.com, it would be the Google mail servers that are responsible for authenticating mail user agents and hence transferring of mails to inboxes on the GMail servers. I'm not sure if GMail trusts open mail relay servers, but it is certainly not an easy task to perform authentication on behalf on Google, and then relay mail to the GMail servers.

If you read the JavaMail FAQ on using JavaMail to accessing GMail, you'll notice that the hostname and the port happen to be pointing to the GMail servers, and certainly not to localhost. If you intend to use your local machine, you'll need to perform either relaying or forwarding.

You'll probably need to understand the SMTP protocol in depth if you intend to get anywhere when it comes to SMTP. You can start with the Wikipedia article on SMTP, but any further progress will actually necessitate programming against a SMTP server.


The following code works very well with Google SMTP server. You need to supply your Google username and password.

import com.sun.mail.smtp.SMTPTransport;
import java.security.Security;
import java.util.Date;
import java.util.Properties;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

/**
 *
 * @author doraemon
 */
public class GoogleMail {
    private GoogleMail() {
    }

    /**
     * Send email using GMail SMTP server.
     *
     * @param username GMail username
     * @param password GMail password
     * @param recipientEmail TO recipient
     * @param title title of the message
     * @param message message to be sent
     * @throws AddressException if the email address parse failed
     * @throws MessagingException if the connection is dead or not in the connected state or if the message is not a MimeMessage
     */
    public static void Send(final String username, final String password, String recipientEmail, String title, String message) throws AddressException, MessagingException {
        GoogleMail.Send(username, password, recipientEmail, "", title, message);
    }

    /**
     * Send email using GMail SMTP server.
     *
     * @param username GMail username
     * @param password GMail password
     * @param recipientEmail TO recipient
     * @param ccEmail CC recipient. Can be empty if there is no CC recipient
     * @param title title of the message
     * @param message message to be sent
     * @throws AddressException if the email address parse failed
     * @throws MessagingException if the connection is dead or not in the connected state or if the message is not a MimeMessage
     */
    public static void Send(final String username, final String password, String recipientEmail, String ccEmail, String title, String message) throws AddressException, MessagingException {
        Security.addProvider(new com.sun.net.ssl.internal.ssl.Provider());
        final String SSL_FACTORY = "javax.net.ssl.SSLSocketFactory";

        // Get a Properties object
        Properties props = System.getProperties();
        props.setProperty("mail.smtps.host", "smtp.gmail.com");
        props.setProperty("mail.smtp.socketFactory.class", SSL_FACTORY);
        props.setProperty("mail.smtp.socketFactory.fallback", "false");
        props.setProperty("mail.smtp.port", "465");
        props.setProperty("mail.smtp.socketFactory.port", "465");
        props.setProperty("mail.smtps.auth", "true");

        /*
        If set to false, the QUIT command is sent and the connection is immediately closed. If set 
        to true (the default), causes the transport to wait for the response to the QUIT command.

        ref :   http://java.sun.com/products/javamail/javadocs/com/sun/mail/smtp/package-summary.html
                http://forum.java.sun.com/thread.jspa?threadID=5205249
                smtpsend.java - demo program from javamail
        */
        props.put("mail.smtps.quitwait", "false");

        Session session = Session.getInstance(props, null);

        // -- Create a new message --
        final MimeMessage msg = new MimeMessage(session);

        // -- Set the FROM and TO fields --
        msg.setFrom(new InternetAddress(username + "@gmail.com"));
        msg.setRecipients(Message.RecipientType.TO, InternetAddress.parse(recipientEmail, false));

        if (ccEmail.length() > 0) {
            msg.setRecipients(Message.RecipientType.CC, InternetAddress.parse(ccEmail, false));
        }

        msg.setSubject(title);
        msg.setText(message, "utf-8");
        msg.setSentDate(new Date());

        SMTPTransport t = (SMTPTransport)session.getTransport("smtps");

        t.connect("smtp.gmail.com", username, password);
        t.sendMessage(msg, msg.getAllRecipients());      
        t.close();
    }
}

Update on 11 December 2015

Username + password is no longer a recommended solution. This is due to

I tried this and Gmail sent the email used as username in this code an email saying that We recently blocked a sign-in attempt to your Google Account, and directed me to this support page: support.google.com/accounts/answer/6010255 so it looks for it to work, the email account being used to send needs to reduce their own security

Google had released Gmail API - https://developers.google.com/gmail/api/?hl=en. We should use oAuth2 method, instead of username + password.

Here's the code snippet to work with Gmail API.

GoogleMail.java

import com.google.api.client.util.Base64;
import com.google.api.services.gmail.Gmail;
import com.google.api.services.gmail.model.Message;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Properties;

import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;

/**
 *
 * @author doraemon
 */
public class GoogleMail {
    private GoogleMail() {
    }

    private static MimeMessage createEmail(String to, String cc, String from, String subject, String bodyText) throws MessagingException {
        Properties props = new Properties();
        Session session = Session.getDefaultInstance(props, null);

        MimeMessage email = new MimeMessage(session);
        InternetAddress tAddress = new InternetAddress(to);
        InternetAddress cAddress = cc.isEmpty() ? null : new InternetAddress(cc);
        InternetAddress fAddress = new InternetAddress(from);

        email.setFrom(fAddress);
        if (cAddress != null) {
            email.addRecipient(javax.mail.Message.RecipientType.CC, cAddress);
        }
        email.addRecipient(javax.mail.Message.RecipientType.TO, tAddress);
        email.setSubject(subject);
        email.setText(bodyText);
        return email;
    }

    private static Message createMessageWithEmail(MimeMessage email) throws MessagingException, IOException {
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        email.writeTo(baos);
        String encodedEmail = Base64.encodeBase64URLSafeString(baos.toByteArray());
        Message message = new Message();
        message.setRaw(encodedEmail);
        return message;
    }

    public static void Send(Gmail service, String recipientEmail, String ccEmail, String fromEmail, String title, String message) throws IOException, MessagingException {
        Message m = createMessageWithEmail(createEmail(recipientEmail, ccEmail, fromEmail, title, message));
        service.users().messages().send("me", m).execute();
    }
}

To construct an authorized Gmail service through oAuth2, here's the code snippet.

Utils.java

import com.google.api.client.auth.oauth2.Credential;
import com.google.api.client.extensions.jetty.auth.oauth2.LocalServerReceiver;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
import com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets;
import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
import com.google.api.client.http.HttpTransport;
import com.google.api.client.json.gson.GsonFactory;
import com.google.api.client.util.store.FileDataStoreFactory;
import com.google.api.services.gmail.Gmail;
import com.google.api.services.gmail.GmailScopes;
import com.google.api.services.oauth2.Oauth2;
import com.google.api.services.oauth2.model.Userinfoplus;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.security.GeneralSecurityException;
import java.util.HashSet;
import java.util.Set;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.yccheok.jstock.engine.Pair;

/**
 *
 * @author yccheok
 */
public class Utils {
    /** Global instance of the JSON factory. */
    private static final GsonFactory JSON_FACTORY = GsonFactory.getDefaultInstance();

    /** Global instance of the HTTP transport. */
    private static HttpTransport httpTransport;

    private static final Log log = LogFactory.getLog(Utils.class);

    static {
        try {
            // initialize the transport
            httpTransport = GoogleNetHttpTransport.newTrustedTransport();

        } catch (IOException ex) {
            log.error(null, ex);
        } catch (GeneralSecurityException ex) {
            log.error(null, ex);
        }
    }

    private static File getGmailDataDirectory() {
        return new File(org.yccheok.jstock.gui.Utils.getUserDataDirectory() + "authentication" + File.separator + "gmail");
    }

    /**
     * Send a request to the UserInfo API to retrieve the user's information.
     *
     * @param credentials OAuth 2.0 credentials to authorize the request.
     * @return User's information.
     * @throws java.io.IOException
     */
    public static Userinfoplus getUserInfo(Credential credentials) throws IOException
    {
        Oauth2 userInfoService =
            new Oauth2.Builder(httpTransport, JSON_FACTORY, credentials).setApplicationName("JStock").build();
        Userinfoplus userInfo  = userInfoService.userinfo().get().execute();
        return userInfo;
    }

    public static String loadEmail(File dataStoreDirectory)  {
        File file = new File(dataStoreDirectory, "email");
        try {
            return new String(Files.readAllBytes(Paths.get(file.toURI())), "UTF-8");
        } catch (IOException ex) {
            log.error(null, ex);
            return null;
        }
    }

    public static boolean saveEmail(File dataStoreDirectory, String email) {
        File file = new File(dataStoreDirectory, "email");
        try {
            //If the constructor throws an exception, the finally block will NOT execute
            BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file), "UTF-8"));
            try {
                writer.write(email);
            } finally {
                writer.close();
            }
            return true;
        } catch (IOException ex){
            log.error(null, ex);
            return false;
        }
    }

    public static void logoutGmail() {
        File credential = new File(getGmailDataDirectory(), "StoredCredential");
        File email = new File(getGmailDataDirectory(), "email");
        credential.delete();
        email.delete();
    }

    public static Pair<Pair<Credential, String>, Boolean> authorizeGmail() throws Exception {
        // Ask for only the permissions you need. Asking for more permissions will
        // reduce the number of users who finish the process for giving you access
        // to their accounts. It will also increase the amount of effort you will
        // have to spend explaining to users what you are doing with their data.
        // Here we are listing all of the available scopes. You should remove scopes
        // that you are not actually using.
        Set<String> scopes = new HashSet<>();

        // We would like to display what email this credential associated to.
        scopes.add("email");

        scopes.add(GmailScopes.GMAIL_SEND);

        // load client secrets
        GoogleClientSecrets clientSecrets = GoogleClientSecrets.load(Utils.JSON_FACTORY,
            new InputStreamReader(Utils.class.getResourceAsStream("/assets/authentication/gmail/client_secrets.json")));

        return authorize(clientSecrets, scopes, getGmailDataDirectory());
    }

    /** Authorizes the installed application to access user's protected data.
     * @return 
     * @throws java.lang.Exception */
    private static Pair<Pair<Credential, String>, Boolean> authorize(GoogleClientSecrets clientSecrets, Set<String> scopes, File dataStoreDirectory) throws Exception {
        // Set up authorization code flow.

        GoogleAuthorizationCodeFlow flow = new GoogleAuthorizationCodeFlow.Builder(
            httpTransport, JSON_FACTORY, clientSecrets, scopes)
            .setDataStoreFactory(new FileDataStoreFactory(dataStoreDirectory))
            .build();
        // authorize
        return new MyAuthorizationCodeInstalledApp(flow, new LocalServerReceiver()).authorize("user");
    }

    public static Gmail getGmail(Credential credential) {
        Gmail service = new Gmail.Builder(httpTransport, JSON_FACTORY, credential).setApplicationName("JStock").build();
        return service;        
    }
}

To provide a user friendly way of oAuth2 authentication, I made use of JavaFX, to display the following input dialog

enter image description here

The key to display user friendly oAuth2 dialog can be found in MyAuthorizationCodeInstalledApp.java and SimpleSwingBrowser.java


Your code works, apart from setting up the connection with the SMTP server. You need a running mail (SMTP) server to send you email for you.

Here is your modified code. I commented out the parts that are not needed and changed the Session creation so it takes an Authenticator. Now just find out the SMPT_HOSTNAME, USERNAME and PASSWORD you want to use (your Internet provider usually provides them).

I always do it like this (using a remote SMTP server I know) because running a local mailserver is not that trivial under Windows (it's apparently quite easy under Linux).

import java.util.*;

import javax.mail.*;
import javax.mail.internet.*;

//import javax.activation.*;

public class SendEmail {

    private static String SMPT_HOSTNAME = "";
    private static String USERNAME = "";
    private static String PASSWORD = "";

    public static void main(String[] args) {

        // Recipient's email ID needs to be mentioned.
        String to = "[email protected]";

        // Sender's email ID needs to be mentioned
        String from = "[email protected]";

        // 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", SMPT_HOSTNAME);

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

        // create a session with an Authenticator
        Session session = Session.getInstance(properties, new Authenticator() {
            @Override
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(USERNAME, PASSWORD);
            }
        });

        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();
        }
    }
}

Indeed 465 works and the exception that you're getting is may be due to the un open SMTP port 25. By default the port number is 25. Yet you can configure it using the mail agent that is available as open source - Mercury

For simplicity, just use the following configuration and you'll be fine.

// Setup your mail server
props.put("mail.smtp.host", SMTP_HOST); 
props.put("mail.smtp.user",FROM_NAME);
props.put("mail.smtp.ssl.enable", "true");
props.put("mail.smtp.port", "25");
props.put("mail.debug", "true");
props.put("mail.smtp.auth", "true");
props.put("mail.smtp.starttls.enable","true");
props.put("mail.smtp.EnableSSL.enable","true");
props.setProperty("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");  
props.setProperty("mail.smtp.socketFactory.fallback", "false");  
props.setProperty("mail.smtp.port", "465");  
props.setProperty("mail.smtp.socketFactory.port", "465");

For even more: check out the complete working example from scratch here


You can find a complete and very simple java class for sending emails using Google(gmail) account here,

Send email using java and Google account

It uses following properties

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

You need a SMTP server for sending mails. There are servers you can install locally on your own pc, or you can use one of the many online servers. One of the more known servers is Google's:

I just successfully tested the allowed Google SMTP configurations using the first example from Simple Java Mail:

    final Email email = EmailBuilder.startingBlank()
        .from("lollypop", "[email protected]")
        .to("C.Cane", "[email protected]")
        .withPlainText("We should meet up!")
        .withHTMLText("<b>We should meet up!</b>")
        .withSubject("hey");

    // starting 5.0.0 do the following using the MailerBuilder instead...
    new Mailer("smtp.gmail.com", 25, "your user", "your password", TransportStrategy.SMTP_TLS).sendMail(email);
    new Mailer("smtp.gmail.com", 587, "your user", "your password", TransportStrategy.SMTP_TLS).sendMail(email);
    new Mailer("smtp.gmail.com", 465, "your user", "your password", TransportStrategy.SMTP_SSL).sendMail(email);

Notice the various ports and transport strategies (which handle all the necessary properties for you).

Curiously, Google require TLS on port 25 as well, even though Google's instructions say otherwise.