Answer by dhiraj kakran for Sending Email in Android using JavaMail API without using the default/built-in app

 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;  }     }