Sending Email in Android using JavaMail API without using the default/built-in app

Send e-mail in Android using the JavaMail API using Gmail authentication.

Steps to create a sample Project:

MailSenderActivity.java:

public class MailSenderActivity extends Activity {
    
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        final Button send = (Button) this.findViewById(R.id.send);
        send.setOnClickListener(new View.OnClickListener() {
            
            public void onClick(View v) {
                try {   
                    GMailSender sender = new GMailSender("username@gmail.com", "password");
                    sender.sendMail("This is Subject",   
                            "This is Body",   
                            "user@gmail.com",   
                            "user@yahoo.com");   
                } catch (Exception e) {   
                    Log.e("SendMail", e.getMessage(), e);   
                } 
                
            }
        });
        
    }
}

GMailSender.java:

public class GMailSender extends javax.mail.Authenticator {   
    private String mailhost = "smtp.gmail.com";   
    private String user;   
    private String password;   
    private Session session;   
  
    static {   
        Security.addProvider(new com.provider.JSSEProvider());   
    }  
  
    public GMailSender(String user, String password) {   
        this.user = user;   
        this.password = password;   
  
        Properties props = new Properties();   
        props.setProperty("mail.transport.protocol", "smtp");   
        props.setProperty("mail.host", mailhost);   
        props.put("mail.smtp.auth", "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");   
        props.setProperty("mail.smtp.quitwait", "false");   
  
        session = Session.getDefaultInstance(props, this);   
    }   
  
    protected PasswordAuthentication getPasswordAuthentication() {   
        return new PasswordAuthentication(user, password);   
    }   
  
    public synchronized void sendMail(String subject, String body, String sender, String recipients) throws Exception {   
        try{
        MimeMessage message = new MimeMessage(session);   
        DataHandler handler = new DataHandler(new ByteArrayDataSource(body.getBytes(), "text/plain"));   
        message.setSender(new InternetAddress(sender));   
        message.setSubject(subject);   
        message.setDataHandler(handler);   
        if (recipients.indexOf(',') > 0)   
            message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(recipients));   
        else  
            message.setRecipient(Message.RecipientType.TO, new InternetAddress(recipients));   
        Transport.send(message);   
        }catch(Exception e){
            
        }
    }   
  
    public class ByteArrayDataSource implements DataSource {   
        private byte[] data;   
        private String type;   
  
        public ByteArrayDataSource(byte[] data, String type) {   
            super();   
            this.data = data;   
            this.type = type;   
        }   
  
        public ByteArrayDataSource(byte[] data) {   
            super();   
            this.data = data;   
        }   
  
        public void setType(String type) {   
            this.type = type;   
        }   
  
        public String getContentType() {   
            if (type == null)   
                return "application/octet-stream";   
            else  
                return type;   
        }   
  
        public InputStream getInputStream() throws IOException {   
            return new ByteArrayInputStream(data);   
        }   
  
        public String getName() {   
            return "ByteArrayDataSource";   
        }   
  
        public OutputStream getOutputStream() throws IOException {   
            throw new IOException("Not Supported");   
        }   
    }   
}  

JSSEProvider.java:

/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

/**
 * @author Alexander Y. Kleymenov
 * @version $Revision$
 */


import java.security.AccessController;
import java.security.Provider;

public final class JSSEProvider extends Provider {

    public JSSEProvider() {
        super("HarmonyJSSE", 1.0, "Harmony JSSE Provider");
        AccessController.doPrivileged(new java.security.PrivilegedAction<Void>() {
            public Void run() {
                put("SSLContext.TLS",
                        "org.apache.harmony.xnet.provider.jsse.SSLContextImpl");
                put("Alg.Alias.SSLContext.TLSv1", "TLS");
                put("KeyManagerFactory.X509",
                        "org.apache.harmony.xnet.provider.jsse.KeyManagerFactoryImpl");
                put("TrustManagerFactory.X509",
                        "org.apache.harmony.xnet.provider.jsse.TrustManagerFactoryImpl");
                return null;
            }
        });
    }
}

ADD 3 jars found in the following link to your Android Project

mail.jar

activation.jar

additional.jar

Click here - How to add External Jars

And don't forget to add this line in your manifest:

<uses-permission android:name="android.permission.INTERNET" />

Just click below link to change account access for less secure apps https://www.google.com/settings/security/lesssecureapps

Run the project and check your recipient mail account for the mail. Cheers!

P.S. And don't forget that you cannot do network operation from any Activity in android. Hence it is recommended to use AsyncTask or IntentService to avoid network on main thread exception.

Jar files: https://code.google.com/archive/p/javamail-android/

---

Thank you for your valuable information. Code is working fine. I am able to add attachment also by adding following code.

private Multipart _multipart; 
_multipart = new MimeMultipart(); 

public void addAttachment(String filename,String subject) throws Exception { 
    BodyPart messageBodyPart = new MimeBodyPart(); 
    DataSource source = new FileDataSource(filename); 
    messageBodyPart.setDataHandler(new DataHandler(source)); 
    messageBodyPart.setFileName(filename); 
    _multipart.addBodyPart(messageBodyPart);

    BodyPart messageBodyPart2 = new MimeBodyPart(); 
    messageBodyPart2.setText(subject); 

    _multipart.addBodyPart(messageBodyPart2); 
} 



message.setContent(_multipart);

---

Could not connect to SMTP host: smtp.gmail.com, port: 465

Add this line in your manifest:

<uses-permission android:name="android.permission.INTERNET" />

---

You can use JavaMail API to handle your email tasks. JavaMail API is available in JavaEE package and its jar is available for download. Sadly it cannot be used directly in an Android application since it uses AWT components which are completely incompatible in Android.

You can find the Android port for JavaMail at the following location: http://code.google.com/p/javamail-android/

Add the jars to your application and use the SMTP method

---

100% working code with demo You can also send multiple emails using this answer.

Download Project HERE

Step 1: Download mail, activation, additional jar files and add in your project libs folder in android studio. I added a screenshot see below Download link

https://i.stack.imgur.com/CCnFj.png

Login with gmail (using your from mail) and TURN ON toggle button LINK

Most of the people forget about this step i hope you will not.

Step 2 : After completing this process. Copy and past this classes into your project.

GMail.java

import android.util.Log;

import java.io.UnsupportedEncodingException;
import java.util.List;
import java.util.Properties;

import javax.mail.Message;
import javax.mail.MessagingException;
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 GMail {

    final String emailPort = "587";// gmail's smtp port
    final String smtpAuth = "true";
    final String starttls = "true";
    final String emailHost = "smtp.gmail.com";


    String fromEmail;
    String fromPassword;
    List<String> toEmailList;
    String emailSubject;
    String emailBody;

    Properties emailProperties;
    Session mailSession;
    MimeMessage emailMessage;

    public GMail() {

    }

    public GMail(String fromEmail, String fromPassword,
            List<String> toEmailList, String emailSubject, String emailBody) {
        this.fromEmail = fromEmail;
        this.fromPassword = fromPassword;
        this.toEmailList = toEmailList;
        this.emailSubject = emailSubject;
        this.emailBody = emailBody;

        emailProperties = System.getProperties();
        emailProperties.put("mail.smtp.port", emailPort);
        emailProperties.put("mail.smtp.auth", smtpAuth);
        emailProperties.put("mail.smtp.starttls.enable", starttls);
        Log.i("GMail", "Mail server properties set.");
    }

    public MimeMessage createEmailMessage() throws AddressException,
            MessagingException, UnsupportedEncodingException {

        mailSession = Session.getDefaultInstance(emailProperties, null);
        emailMessage = new MimeMessage(mailSession);

        emailMessage.setFrom(new InternetAddress(fromEmail, fromEmail));
        for (String toEmail : toEmailList) {
            Log.i("GMail", "toEmail: " + toEmail);
            emailMessage.addRecipient(Message.RecipientType.TO,
                    new InternetAddress(toEmail));
        }

        emailMessage.setSubject(emailSubject);
        emailMessage.setContent(emailBody, "text/html");// for a html email
        // emailMessage.setText(emailBody);// for a text email
        Log.i("GMail", "Email Message created.");
        return emailMessage;
    }

    public void sendEmail() throws AddressException, MessagingException {

        Transport transport = mailSession.getTransport("smtp");
        transport.connect(emailHost, fromEmail, fromPassword);
        Log.i("GMail", "allrecipients: " + emailMessage.getAllRecipients());
        transport.sendMessage(emailMessage, emailMessage.getAllRecipients());
        transport.close();
        Log.i("GMail", "Email sent successfully.");
    }

}

SendMailTask.java

import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.util.Log;

import java.util.List;

public class SendMailTask extends AsyncTask {

    private ProgressDialog statusDialog;
    private Activity sendMailActivity;

    public SendMailTask(Activity activity) {
        sendMailActivity = activity;

    }

    protected void onPreExecute() {
        statusDialog = new ProgressDialog(sendMailActivity);
        statusDialog.setMessage("Getting ready...");
        statusDialog.setIndeterminate(false);
        statusDialog.setCancelable(false);
        statusDialog.show();
    }

    @Override
    protected Object doInBackground(Object... args) {
        try {
            Log.i("SendMailTask", "About to instantiate GMail...");
            publishProgress("Processing input....");
            GMail androidEmail = new GMail(args[0].toString(),
                    args[1].toString(), (List) args[2], args[3].toString(),
                    args[4].toString());
            publishProgress("Preparing mail message....");
            androidEmail.createEmailMessage();
            publishProgress("Sending email....");
            androidEmail.sendEmail();
            publishProgress("Email Sent.");
            Log.i("SendMailTask", "Mail Sent.");
        } catch (Exception e) {
            publishProgress(e.getMessage());
            Log.e("SendMailTask", e.getMessage(), e);
        }
        return null;
    }

    @Override
    public void onProgressUpdate(Object... values) {
        statusDialog.setMessage(values[0].toString());

    }

    @Override
    public void onPostExecute(Object result) {
        statusDialog.dismiss();
    }

}

Step 3 : Now you can change this class according to your needs also you can send multiple mail using this class. i provide xml and java file both.

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingLeft="20dp"
    android:paddingRight="20dp"
    android:paddingTop="30dp">

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingTop="10dp"
        android:text="From Email" />

    <EditText
        android:id="@+id/editText1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#FFFFFF"
        android:cursorVisible="true"
        android:editable="true"
        android:ems="10"
        android:enabled="true"
        android:inputType="textEmailAddress"
        android:padding="5dp"
        android:textColor="#000000">

        <requestFocus />
    </EditText>

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingTop="10dp"
        android:text="Password (For from email)" />

    <EditText
        android:id="@+id/editText2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#FFFFFF"
        android:ems="10"
        android:inputType="textPassword"
        android:padding="5dp"
        android:textColor="#000000" />

    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingTop="10dp"
        android:text="To Email" />

    <EditText
        android:id="@+id/editText3"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#ffffff"
        android:ems="10"
        android:inputType="textEmailAddress"
        android:padding="5dp"
        android:textColor="#000000" />

    <TextView
        android:id="@+id/textView4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingTop="10dp"
        android:text="Subject" />

    <EditText
        android:id="@+id/editText4"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#ffffff"
        android:ems="10"
        android:padding="5dp"
        android:textColor="#000000" />

    <TextView
        android:id="@+id/textView5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingTop="10dp"
        android:text="Body" />

    <EditText
        android:id="@+id/editText5"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#ffffff"
        android:ems="10"
        android:inputType="textMultiLine"
        android:padding="35dp"
        android:textColor="#000000" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Send Email" />

</LinearLayout>

SendMailActivity.java

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import java.util.Arrays;
import java.util.List;

public class SendMailActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final Button send = (Button) this.findViewById(R.id.button1);

        send.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {
                Log.i("SendMailActivity", "Send Button Clicked.");

                String fromEmail = ((TextView) findViewById(R.id.editText1))
                        .getText().toString();
                String fromPassword = ((TextView) findViewById(R.id.editText2))
                        .getText().toString();
                String toEmails = ((TextView) findViewById(R.id.editText3))
                        .getText().toString();
                List<String> toEmailList = Arrays.asList(toEmails
                        .split("\\s*,\\s*"));
                Log.i("SendMailActivity", "To List: " + toEmailList);
                String emailSubject = ((TextView) findViewById(R.id.editText4))
                        .getText().toString();
                String emailBody = ((TextView) findViewById(R.id.editText5))
                        .getText().toString();
                new SendMailTask(SendMailActivity.this).execute(fromEmail,
                        fromPassword, toEmailList, emailSubject, emailBody);
            }
        });
    }
}

Note Dont forget to add internet permission in your AndroidManifest.xml file

<uses-permission android:name="android.permission.INTERNET"/>

Hope it work if it not then just comment down below.

---

In order to help those getting a Network On Main Thread Exception with an SDK Target >9. This is using droopie's code above but will work similarly for any.

StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();

StrictMode.setThreadPolicy(policy); 

android.os.NetworkOnMainThreadException

You can use AsyncTask as below

public void onClickMail(View view) {
    new SendEmailAsyncTask().execute();
}

class SendEmailAsyncTask extends AsyncTask <Void, Void, Boolean> {
    Mail m = new Mail("from@gmail.com", "my password");

    public SendEmailAsyncTask() {
        if (BuildConfig.DEBUG) Log.v(SendEmailAsyncTask.class.getName(), "SendEmailAsyncTask()");
        String[] toArr = { "to mail@gmail.com"};
        m.setTo(toArr);
        m.setFrom("from mail@gmail.com");
        m.setSubject("Email from Android");
        m.setBody("body.");
    }

    @Override
    protected Boolean doInBackground(Void... params) {
        if (BuildConfig.DEBUG) Log.v(SendEmailAsyncTask.class.getName(), "doInBackground()");
        try {
            m.send();
            return true;
        } catch (AuthenticationFailedException e) {
            Log.e(SendEmailAsyncTask.class.getName(), "Bad account details");
            e.printStackTrace();
            return false;
        } catch (MessagingException e) {
            Log.e(SendEmailAsyncTask.class.getName(), m.getTo(null) + "failed");
            e.printStackTrace();
            return false;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }

---

SMTP

Using SMTP is one way to go, and the others have already pointed out ways how to do it. Just note that while doing this, you completely circumvent the built in mail app, and you will have to provide the address of the SMTP server, the user name and password for that server, either statically in your code, or query it from the user.

HTTP

Another way would involve a simple server side script, like php, that takes some URL parameters and uses them to send a mail. This way, you only need to make an HTTP request from the device (easily possible with the built in libraries) and don't need to store the SMTP login data on the device. This is one more indirection compared to direct SMTP usage, but because it's so very easy to make HTTP request and send mails from PHP, it might even be simpler than the direct way.

Mail Application

If the mail shall be send from the users default mail account that he already registered with the phone, you'd have to take some other approach. If you have enough time and experience, you might want to check the source code of the Android Email application to see if it offers some entry point to send a mail without user interaction (I don't know, but maybe there is one).

Maybe you even find a way to query the users account details (so you can use them for SMTP), though I highly doubt that this is possible, because it would be a huge security risk and Android is built rather securely.

---

here is an alt version that also works for me and has attachments (posted already above but complete version unlike the source link, which people posted they cant get it to work since its missing data)

import java.util.Date; 
import java.util.Properties; 
import javax.activation.CommandMap; 
import javax.activation.DataHandler; 
import javax.activation.DataSource; 
import javax.activation.FileDataSource; 
import javax.activation.MailcapCommandMap; 
import javax.mail.BodyPart; 
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 Mail extends javax.mail.Authenticator { 
  private String _user; 
  private String _pass; 

  private String[] _to; 
  private String _from; 

  private String _port; 
  private String _sport; 

  private String _host; 

  private String _subject; 
  private String _body; 

  private boolean _auth; 

  private boolean _debuggable; 

  private Multipart _multipart; 


  public Mail() { 
    _host = "smtp.gmail.com"; // default smtp server 
    _port = "465"; // default smtp port 
    _sport = "465"; // default socketfactory port 

    _user = ""; // username 
    _pass = ""; // password 
    _from = ""; // email sent from 
    _subject = ""; // email subject 
    _body = ""; // email body 

    _debuggable = false; // debug mode on or off - default off 
    _auth = true; // smtp authentication - default on 

    _multipart = new MimeMultipart(); 

    // There is something wrong with MailCap, javamail can not find a handler for the multipart/mixed part, so this bit needs to be added. 
    MailcapCommandMap mc = (MailcapCommandMap) CommandMap.getDefaultCommandMap(); 
    mc.addMailcap("text/html;; x-java-content-handler=com.sun.mail.handlers.text_html"); 
    mc.addMailcap("text/xml;; x-java-content-handler=com.sun.mail.handlers.text_xml"); 
    mc.addMailcap("text/plain;; x-java-content-handler=com.sun.mail.handlers.text_plain"); 
    mc.addMailcap("multipart/*;; x-java-content-handler=com.sun.mail.handlers.multipart_mixed"); 
    mc.addMailcap("message/rfc822;; x-java-content-handler=com.sun.mail.handlers.message_rfc822"); 
    CommandMap.setDefaultCommandMap(mc); 
  } 

  public Mail(String user, String pass) { 
    this(); 

    _user = user; 
    _pass = pass; 
  } 

  public boolean send() throws Exception { 
    Properties props = _setProperties(); 

    if(!_user.equals("") && !_pass.equals("") && _to.length > 0 && !_from.equals("") && !_subject.equals("") && !_body.equals("")) { 
      Session session = Session.getInstance(props, this); 

      MimeMessage msg = new MimeMessage(session); 

      msg.setFrom(new InternetAddress(_from)); 

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

      msg.setSubject(_subject); 
      msg.setSentDate(new Date()); 

      // setup message body 
      BodyPart messageBodyPart = new MimeBodyPart(); 
      messageBodyPart.setText(_body); 
      _multipart.addBodyPart(messageBodyPart); 

      // Put parts in message 
      msg.setContent(_multipart); 

      // send email 
      Transport.send(msg); 

      return true; 
    } else { 
      return false; 
    } 
  } 

  public void addAttachment(String filename) throws Exception { 
    BodyPart messageBodyPart = new MimeBodyPart(); 
    DataSource source = new FileDataSource(filename); 
    messageBodyPart.setDataHandler(new DataHandler(source)); 
    messageBodyPart.setFileName(filename); 

    _multipart.addBodyPart(messageBodyPart); 
  } 

  @Override 
  public PasswordAuthentication getPasswordAuthentication() { 
    return new PasswordAuthentication(_user, _pass); 
  } 

  private Properties _setProperties() { 
    Properties props = new Properties(); 

    props.put("mail.smtp.host", _host); 

    if(_debuggable) { 
      props.put("mail.debug", "true"); 
    } 

    if(_auth) { 
      props.put("mail.smtp.auth", "true"); 
    } 

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

    return props; 
  } 

  // the getters and setters 
  public String getBody() { 
    return _body; 
  } 

  public void setBody(String _body) { 
    this._body = _body; 
  }

  public void setTo(String[] toArr) {
      // TODO Auto-generated method stub
      this._to=toArr;
  }

  public void setFrom(String string) {
      // TODO Auto-generated method stub
      this._from=string;
  }

  public void setSubject(String string) {
      // TODO Auto-generated method stub
      this._subject=string;
  }  

  // more of the getters and setters ….. 
}

and to call it in an activity...

@Override 
public void onCreate(Bundle icicle) { 
  super.onCreate(icicle); 
  setContentView(R.layout.main); 

  Button addImage = (Button) findViewById(R.id.send_email); 
  addImage.setOnClickListener(new View.OnClickListener() { 
    public void onClick(View view) { 
      Mail m = new Mail("gmailusername@gmail.com", "password"); 

      String[] toArr = {"bla@bla.com", "lala@lala.com"}; 
      m.setTo(toArr); 
      m.setFrom("wooo@wooo.com"); 
      m.setSubject("This is an email sent using my Mail JavaMail wrapper from an Android device."); 
      m.setBody("Email body."); 

      try { 
        m.addAttachment("/sdcard/filelocation"); 

        if(m.send()) { 
          Toast.makeText(MailApp.this, "Email was sent successfully.", Toast.LENGTH_LONG).show(); 
        } else { 
          Toast.makeText(MailApp.this, "Email was not sent.", Toast.LENGTH_LONG).show(); 
        } 
      } catch(Exception e) { 
        //Toast.makeText(MailApp.this, "There was a problem sending the email.", Toast.LENGTH_LONG).show(); 
        Log.e("MailApp", "Could not send email", e); 
      } 
    } 
  }); 
} 

---

GmailBackground is small library to send an email in background without user interaction :

Usage:

    BackgroundMail.newBuilder(this)
            .withUsername("username@gmail.com")
            .withPassword("password12345")
            .withMailto("toemail@gmail.com")
            .withType(BackgroundMail.TYPE_PLAIN)
            .withSubject("this is the subject")
            .withBody("this is the body")
            .withOnSuccessCallback(new BackgroundMail.OnSuccessCallback() {
                @Override
                public void onSuccess() {
                    //do some magic
                }
            })
            .withOnFailCallback(new BackgroundMail.OnFailCallback() {
                @Override
                public void onFail() {
                    //do some magic
                }
            })
            .send();

Configuration:

repositories {
    // ...
    maven { url "https://jitpack.io" }
 }
 dependencies {
            compile 'com.github.yesidlazaro:GmailBackground:1.2.0'
    }

Permissions:

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.INTERNET"/>

Also for attachments, you need to set READ_EXTERNAL_STORAGE permission:

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

Source

(I've tested it myself)

---

Word of warning if using "smtp.gmail.com" as the default smtp server.

Google will force you to change your linked email account password frequently due to their over zealous "suspicious activity" polices. In essence it treats repeated smtp requests from different countries within a short time frame as "suspicious activity". As they assume you (the email account holder) can only be in one country at a time.

When google systems detect "suspicious activity" it will prevent further emails until you change the password. As you will have hard coded the password into the app you have to re-release the app each time this happens, not ideal. This happened 3 times in a week to me, I even stored the password on another server and dynamically fetched the password each time google forced me to change it.

So I recommend using one of the many free smtp providers instead of "smtp.gmail.com" to avoid this security problem. Use the same code but change "smtp.gmail.com" to your new smtp forwarding host.

---

Edit: JavaMail 1.5.5 claims to support Android, so you shouldn't need anything else.

I've ported the latest JavaMail (1.5.4) to Android. It's available in Maven Central, just add the following to build.gradle~~

compile 'eu.ocathain.com.sun.mail:javax.mail:1.5.4' You can then follow the official tutorial. Source code is available here: https://bitbucket.org/artbristol/javamail-forked-android

---

I found a shorter alternative for others who need help. The code is:

package com.example.mail;

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 SendMailTLS {

    public static void main(String[] args) {

        final String username = "username@gmail.com";
        final String password = "password";

        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");

        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("from-email@gmail.com"));
            message.setRecipients(Message.RecipientType.TO,
                InternetAddress.parse("to-email@gmail.com"));
            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);
        }
    }
}

Source: Sending Email via JavaMail API

Hope this Helps! Good Luck!

---

For sending a mail with attachment..

public class SendAttachment{
                    public static void main(String [] args){ 
             //to address
                    String to="abc@abc.com";//change accordingly
                    //from address
                    final String user="efg@efg.com";//change accordingly
                    final String password="password";//change accordingly 
                     MailcapCommandMap mc = (MailcapCommandMap) CommandMap.getDefaultCommandMap();
                   mc.addMailcap("text/html;; x-java-content-handler=com.sun.mail.handlers.text_html");
                  mc.addMailcap("text/xml;; x-java-content-handler=com.sun.mail.handlers.text_xml");
                  mc.addMailcap("text/plain;; x-java-content-handler=com.sun.mail.handlers.text_plain");
                  mc.addMailcap("multipart/*;; x-java-content-handler=com.sun.mail.handlers.multipart_mixed");
                  mc.addMailcap("message/rfc822;; x-java-content-handler=com.sun.mail.handlers.message_rfc822");
                  CommandMap.setDefaultCommandMap(mc); 
                  //1) get the session object   
                  Properties properties = System.getProperties();
                  properties.put("mail.smtp.port", "465"); 
                  properties.put("mail.smtp.host", "smtp.gmail.com");
                    properties.put("mail.smtp.socketFactory.port", "465");
                    properties.put("mail.smtp.socketFactory.class",
                            "javax.net.ssl.SSLSocketFactory");
                    properties.put("mail.smtp.auth", "true");
                    properties.put("mail.smtp.port", "465");

                  Session session = Session.getDefaultInstance(properties,
                   new javax.mail.Authenticator() {
                   protected PasswordAuthentication getPasswordAuthentication() {
                   return new PasswordAuthentication(user,password);
                   }
                  });

                  //2) compose message   
                  try{ 
                    MimeMessage message = new MimeMessage(session);
                    message.setFrom(new InternetAddress(user));
                    message.addRecipient(Message.RecipientType.TO,new InternetAddress(to));
                    message.setSubject("Hii"); 
                    //3) create MimeBodyPart object and set your message content    
                    BodyPart messageBodyPart1 = new MimeBodyPart();
                    messageBodyPart1.setText("How is This"); 
                    //4) create new MimeBodyPart object and set DataHandler object to this object    
                    MimeBodyPart messageBodyPart2 = new MimeBodyPart();
                //Location of file to be attached
                    String filename = Environment.getExternalStorageDirectory().getPath()+"/R2832.zip";//change accordingly
                    DataSource source = new FileDataSource(filename);
                    messageBodyPart2.setDataHandler(new DataHandler(source));
                    messageBodyPart2.setFileName("Hello"); 
                    //5) create Multipart object and add MimeBodyPart objects to this object    
                    Multipart multipart = new MimeMultipart();
                    multipart.addBodyPart(messageBodyPart1);
                    multipart.addBodyPart(messageBodyPart2); 
                    //6) set the multiplart object to the message object
                    message.setContent(multipart ); 
                    //7) send message 
                    Transport.send(message); 
                   System.out.println("MESSAGE SENT....");
                   }catch (MessagingException ex) {ex.printStackTrace();}
                  }
                }

---

Those who are getting ClassDefNotFoundError try to move that Three jar files to lib folder of your Project,it worked for me!!

---

I am unable to run Vinayak B's code. Finally i solved this issue by following :

1.Using this

2.Applying AsyncTask.

3.Changing security issue of sender gmail account.(Change to "TURN ON") in this

---

Did you consider using Apache Commons Net ? Since 3.3, just one jar (and you can depend on it using gradle or maven) and you're done : http://blog.dahanne.net/2013/06/17/sending-a-mail-in-java-and-android-with-apache-commons-net/

---

Without user intervention, you can send as follows:

Send email from client apk. Here mail.jar, activation.jar is required to send java email. If these jars are added, it might increase the APK Size. Alternatively, You can use a web-service at the server side code, which will use the same mail.jar and activation.jar to send email. You can call the web-service via asynctask and send email. Refer same link.

(But, you will need to know the credentials of the mail account)

---

In case that you are demanded to keep the jar library as small as possible, you can include the SMTP/POP3/IMAP function separately to avoid the "too many methods in the dex" problem.

You can choose the wanted jar libraries from the javanet web page, for example, mailapi.jar + imap.jar can enable you to access icloud, hotmail mail server in IMAP protocol. (with the help of additional.jar and activation.jar)

---

I tried using the code that @Vinayak B submitted. However I'm getting an error saying: No provider for smtp

I created a new question for this with more information HERE

I was able to fix it myself after all. I had to use an other mail.jar and I had to make sure my "access for less secure apps" was turned on.

I hope this helps anyone who has the same problem. With this done, this piece of code works on the google glass too.

---

All the code provided in the other answers is correct and is working fine, but a bit messy, so I decided to publish a library (still in development though) to use it in a easier way: AndroidMail.

You have just to create a MailSender, build a mail and send it (already handled in background with an AsyncTask).

MailSender mailSender = new MailSender(email, password);

Mail.MailBuilder builder = new Mail.MailBuilder();
Mail mail = builder
    .setSender(senderMail)
    .addRecipient(new Recipient(recipient))
    .setText("Hello")
    .build();

mailSender.sendMail(mail);

You can receive a notification for the email sent and it has also the support for different Recipients types (TO, CC and BCC), attachments and html:

MailSender mailSender = new MailSender(email, password);

Mail.MailBuilder builder = new Mail.MailBuilder();
Mail mail = builder
    .setSender(senderMail)
    .addRecipient(new Recipient(recipient))
    .addRecipient(new Recipient(Recipient.TYPE.CC, recipientCC))
    .setText("Hello")
    .setHtml("<h1 style=\"color:red;\">Hello</h1>")
    .addAttachment(new Attachment(filePath, fileName))
    .build();

mailSender.sendMail(mail, new MailSender.OnMailSentListener() {

    @Override
    public void onSuccess() {
        // mail sent!
    }

    @Override
    public void onError(Exception error) {
        // something bad happened :(
    }
});

You can get it via Gradle or Maven:

compile 'it.enricocandino:androidmail:1.0.0-SNAPSHOT'

Please let me know if you have any issue with it! :)

---

Here are a lot solutions. However I think we must change the configuration of the GMail to allow accessing from less secure devices. Go to the link below and enable it. It works for me

https://myaccount.google.com/lesssecureapps?pli=1

---

Sending email programmatically with Kotlin.

simple email sending, not all the other features (like attachments).

TLS is always on

Only 1 gradle email dependency needed also.

I also found this list of email POP services really helpful:

https://support.office.com/en-gb/article/pop-and-imap-email-settings-for-outlook-8361e398-8af4-4e97-b147-6c6c4ac95353

How to use:

    val auth = EmailService.UserPassAuthenticator("you@gmail.com", "yourPassword")
    val to = listOf(InternetAddress("to@email.com"))
    val from = InternetAddress("you@gmail.com")
    val email = EmailService.Email(auth, to, from, "Test Subject", "Hello Body World")
    val emailService = EmailService("smtp.gmail.com", 465)
    
    GlobalScope.launch { // or however you do background threads
        emailService.send(email)
    }

The code:

import java.util.*
import javax.mail.*
import javax.mail.internet.InternetAddress
import javax.mail.internet.MimeBodyPart
import javax.mail.internet.MimeMessage
import javax.mail.internet.MimeMultipart

class EmailService(private val server: String, private val port: Int) {

    data class Email(
        val auth: Authenticator,
        val toList: List<InternetAddress>,
        val from: Address,
        val subject: String,
        val body: String
    )

    class UserPassAuthenticator(private val username: String, private val password: String) : Authenticator() {
        override fun getPasswordAuthentication(): PasswordAuthentication {
            return PasswordAuthentication(username, password)
        }
    }

    fun send(email: Email) {
        val props = Properties()
        props["mail.smtp.auth"] = "true"
        props["mail.user"] = email.from
        props["mail.smtp.host"] = server
        props["mail.smtp.port"] = port
        props["mail.smtp.starttls.enable"] = "true"
        props["mail.smtp.ssl.trust"] = server
        props["mail.mime.charset"] = "UTF-8"
        val msg: Message = MimeMessage(Session.getDefaultInstance(props, email.auth))
        msg.setFrom(email.from)
        msg.sentDate = Calendar.getInstance().time
        msg.setRecipients(Message.RecipientType.TO, email.toList.toTypedArray())
//      msg.setRecipients(Message.RecipientType.CC, email.ccList.toTypedArray())
//      msg.setRecipients(Message.RecipientType.BCC, email.bccList.toTypedArray())
        msg.replyTo = arrayOf(email.from)

        msg.addHeader("X-Mailer", CLIENT_NAME)
        msg.addHeader("Precedence", "bulk")
        msg.subject = email.subject

        msg.setContent(MimeMultipart().apply {
            addBodyPart(MimeBodyPart().apply {
                setText(email.body, "iso-8859-1")
                //setContent(email.htmlBody, "text/html; charset=UTF-8")
            })
        })
        Transport.send(msg)
    }

    companion object {
        const val CLIENT_NAME = "Android StackOverflow programmatic email"
    }
}

Gradle:

dependencies {
    implementation 'com.sun.mail:android-mail:1.6.4'
    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.3"
}

AndroidManifest:

<uses-permission android:name="android.permission.INTERNET" />

---

 Add jar files mail.jar,activation.jar,additionnal.jar

 String sub="Thank you for your online registration" ; 
 Mail m = new Mail("emailid", "password"); 

 String[] toArr = {"ekkatrainfo@gmail.com",sEmailId};
 m.setFrom("ekkatrainfo@gmail.com"); 

     m.setTo(toArr);
     m.setSubject(sub);
    m.setBody(msg);



                     try{


                            if(m.send()) { 

                            } else { 

                            } 
                          } catch(Exception e) { 

                            Log.e("MailApp", "Could not send email", e); 
                          } 

  package com.example.ekktra;

   import java.util.Date;
   import java.util.Properties;

   import javax.activation.CommandMap;
   import javax.activation.DataHandler;
   import javax.activation.DataSource;
   import javax.activation.FileDataSource;
   import javax.activation.MailcapCommandMap;
   import javax.mail.BodyPart;
   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 Mail extends javax.mail.Authenticator { 
     private String _user; 
     private String _pass; 

     private String[] _to; 

     private String _from; 

     private String _port; 
     private String _sport; 

     private String _host; 

     private String _subject; 
     private String _body; 

     private boolean _auth; 

     private boolean _debuggable; 

     private Multipart _multipart; 


   public Mail() { 
      _host = "smtp.gmail.com"; // default smtp server 
      _port = "465"; // default smtp port 
      _sport = "465"; // default socketfactory port 

      _user = ""; // username 
      _pass = ""; // password 
      _from = ""; // email sent from 
      _subject = ""; // email subject 
      _body = ""; // email body 

      _debuggable = false; // debug mode on or off - default off 
      _auth = true; // smtp authentication - default on 

      _multipart = new MimeMultipart(); 

      // There is something wrong with MailCap, javamail can not find a handler for the        multipart/mixed part, so this bit needs to be added. 
      MailcapCommandMap mc = (MailcapCommandMap) CommandMap.getDefaultCommandMap(); 
   mc.addMailcap("text/html;; x-java-content-handler=com.sun.mail.handlers.text_html"); 
   mc.addMailcap("text/xml;; x-java-content-handler=com.sun.mail.handlers.text_xml"); 
   mc.addMailcap("text/plain;; x-java-content-  handler=com.sun.mail.handlers.text_plain"); 
   mc.addMailcap("multipart/*;; x-java-content-handler=com.sun.mail.handlers.multipart_mixed"); 
   mc.addMailcap("message/rfc822;; x-java-content- handler=com.sun.mail.handlers.message_rfc822"); 
    CommandMap.setDefaultCommandMap(mc); 
   } 

 public Mail(String user, String pass) { 
  this(); 

  _user = user; 
   _pass = pass; 
 } 

public boolean send() throws Exception { 
   Properties props = _setProperties(); 

  if(!_user.equals("") && !_pass.equals("") && _to.length > 0 && !_from.equals("") &&   !_subject.equals("") /*&& !_body.equals("")*/) { 
    Session session = Session.getInstance(props, this); 

    MimeMessage msg = new MimeMessage(session); 

     msg.setFrom(new InternetAddress(_from)); 

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

    msg.setSubject(_subject); 
    msg.setSentDate(new Date()); 

  // setup message body 
  BodyPart messageBodyPart = new MimeBodyPart(); 
    messageBodyPart.setText(_body); 
    _multipart.addBodyPart(messageBodyPart); 

     // Put parts in message 
    msg.setContent(_multipart); 

    // send email 
    Transport.send(msg); 

    return true; 
   } else { 
     return false; 
   } 
  } 

   public void addAttachment(String filename) throws Exception { 
    BodyPart messageBodyPart = new MimeBodyPart(); 
    DataSource source = new FileDataSource(filename); 
      messageBodyPart.setDataHandler(new DataHandler(source)); 
    messageBodyPart.setFileName(filename); 

   _multipart.addBodyPart(messageBodyPart); 
 } 

  @Override 
  public PasswordAuthentication getPasswordAuthentication() { 
     return new PasswordAuthentication(_user, _pass); 
  } 

   private Properties _setProperties() { 
   Properties props = new Properties(); 

    props.put("mail.smtp.host", _host); 

  if(_debuggable) { 
    props.put("mail.debug", "true"); 
  } 

  if(_auth) { 
    props.put("mail.smtp.auth", "true"); 
   } 

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

    return props; 
   } 

   // the getters and setters 
  public String getBody() { 
   return _body; 
 } 

 public void setBody(String _body) { 
  this._body = _body; 
 }

  public void setTo(String[] toArr) {
     // TODO Auto-generated method stub
    this._to=toArr;
 }

public void setFrom(String string) {
    // TODO Auto-generated method stub
    this._from=string;
}

 public void setSubject(String string) {
    // TODO Auto-generated method stub
    this._subject=string;
  }  


   }

---

For those who want to use JavaMail with Kotlin in 2020:

First: Add these dependencies to your build.gradle file (official JavaMail Maven Dependencies)

implementation 'com.sun.mail:android-mail:1.6.5' implementation 'com.sun.mail:android-activation:1.6.5'

implementation "org.bouncycastle:bcmail-jdk15on:1.65" implementation "org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.7" implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.7"

BouncyCastle is for security reasons.

Second: Add these permissions to your AndroidManifest.xml

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

Third: When using SMTP, create a Config file

object Config {
    const val EMAIL_FROM = "You_Sender_Email@email.com"
    const val PASS_FROM = "Your_Sender_Password"

    const val EMAIL_TO = "Your_Destination_Email@email.com"
}

Fourth: Create your Mailer Object

object Mailer {

init {
    Security.addProvider(BouncyCastleProvider())
}

private fun props(): Properties = Properties().also {
        // Smtp server
        it["mail.smtp.host"] = "smtp.gmail.com"
        // Change when necessary
        it["mail.smtp.auth"] = "true"
        it["mail.smtp.port"] = "465"
        // Easy and fast way to enable ssl in JavaMail
        it["mail.smtp.ssl.enable"] = true
    }

// Dont ever use "getDefaultInstance" like other examples do!
private fun session(emailFrom: String, emailPass: String): Session = Session.getInstance(props(), object : Authenticator() {
    override fun getPasswordAuthentication(): PasswordAuthentication {
        return PasswordAuthentication(emailFrom, emailPass)
    }
})

private fun builtMessage(firstName: String, surName: String): String {
    return """
            <b>Name:</b> $firstName  <br/>
            <b>Surname:</b> $surName <br/>
        """.trimIndent()
}

private fun builtSubject(issue: String, firstName: String, surName: String):String {
    return """
            $issue | $firstName, $surName
        """.trimIndent()
}

private fun sendMessageTo(emailFrom: String, session: Session, message: String, subject: String) {
    try {
        MimeMessage(session).let { mime ->
            mime.setFrom(InternetAddress(emailFrom))
            // Adding receiver
            mime.addRecipient(Message.RecipientType.TO, InternetAddress(Config.EMAIL_TO))
            // Adding subject
            mime.subject = subject
            // Adding message
            mime.setText(message)
            // Set Content of Message to Html if needed
            mime.setContent(message, "text/html")
            // send mail
            Transport.send(mime)
        }

    } catch (e: MessagingException) {
        Log.e("","") // Or use timber, it really doesn't matter
    }
}

fun sendMail(firstName: String, surName: String) {
        // Open a session
        val session = session(Config.EMAIL_FROM, Config.PASSWORD_FROM)

        // Create a message
        val message = builtMessage(firstName, surName)

        // Create subject
        val subject = builtSubject(firstName, surName)

        // Send Email
        CoroutineScope(Dispatchers.IO).launch { sendMessageTo(Config.EMAIL_FROM, session, message, subject) }
}

Note

If you want a more secure way to send your email (and you want a more secure way!), use http as mentioned in the solutions before (I will maybe add it later in this answer)

You have to properly check, if the users phone has internet access, otherwise the app will crash.

When using gmail, enable "less secure apps" (this will not work, when you gmail has two factors enabled) https://myaccount.google.com/lesssecureapps?pli=1

Some credits belong to: https://medium.com/@chetan.garg36/android-send-mails-not-intent-642d2a71d2ee (he used RxJava for his solution)

---

package io.formics.tourguide

import android.annotation.SuppressLint
import android.content.Intent
import android.net.Credentials
import android.net.Uri
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import android.widget.Toast
import kotlinx.android.synthetic.main.activity_feedback.*
import org.jetbrains.annotations.Async
import java.lang.Exception

import java.util.Properties;


import javax.activation.DataHandler;
import javax.activation.FileDataSource
import javax.mail.*
import javax.mail.internet.*


class FeedbackActivity : AppCompatActivity()  {
  
    val props = Properties()


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_feedback)

        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");

        btnSendEmail.setOnClickListener {
            Thread {
                try {
                    sendEmail()
                    // Your implementation
                } catch (ex: Exception) {
                    ex.printStackTrace()
                }
            }.start()


        }
    }


    private fun sendEmail() {



        try {

            val session = Session.getInstance(props,
                object : javax.mail.Authenticator() {
                    //Authenticating the password
                    override fun getPasswordAuthentication(): javax.mail.PasswordAuthentication {
                        return PasswordAuthentication("abc@xyz.com", "password")
                    }
                })

            val message = MimeMessage(session);
            message.setFrom(InternetAddress("abc@xyz.com"));
            message.setRecipients(
                Message.RecipientType.TO,
                InternetAddress.parse(editCC.text.toString())
            )
            message.subject = editSubject.text.toString()
            message.setText(
                "Dear Mail Crawler,"
                        + "\n\n No spam to my email, please!"
            );

            //val messageBodyPart = MimeBodyPart();

            //val multipart = MimeMultipart();

            //val file = "path of file to be attached";

//            val fileName = "attachmentName"
           // val source = FileDataSource(file);
            //messageBodyPart.setDataHandler(DataHandler(source));
            //messageBodyPart.setFileName(fileName);
            //multipart.addBodyPart(messageBodyPart);

            //message.setContent(multipart);

            Transport.send(message);
            System.out.println("Done");



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

           }
}




 

---

To add attachment, don't forget to add.

MailcapCommandMap mc = (MailcapCommandMap) CommandMap
            .getDefaultCommandMap();
    mc.addMailcap("text/html;; x-java-content-handler=com.sun.mail.handlers.text_html");
    mc.addMailcap("text/xml;; x-java-content-handler=com.sun.mail.handlers.text_xml");
    mc.addMailcap("text/plain;; x-java-content-handler=com.sun.mail.handlers.text_plain");
    mc.addMailcap("multipart/*;; x-java-content-handler=com.sun.mail.handlers.multipart_mixed");
    mc.addMailcap("message/rfc822;; x-java-content-handler=com.sun.mail.handlers.message_rfc822");
    CommandMap.setDefaultCommandMap(mc);

---