Why I am getting javax.mail.MessagingException ?

Question

I am trying to send mail from the Servlet. I had code like this and I am getting the Messaging Exception. There are many other similar questions in Stack Over Flow but none of them helped me. So I posted it again.

@WebServlet(name = "SendMail", urlPatterns = {"/SendMail"})
public class SendMail extends HttpServlet {
final String from = "teamwarrior20@gmail.com";
final String username = "teamwarrior20@gmail.com";
final String password = "iamfromnepal";
String to;
String subject;
String dataMessage;

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    to = req.getParameter("to");
    subject = req.getParameter("subject");
    dataMessage = req.getParameter("message");
    sendMail();
    req.getRequestDispatcher("successfullmail.jsp").forward(req, resp);
}

private void sendMail() {
    System.out.println(to);
    System.out.println(subject);
    System.out.println(dataMessage);
    Properties props = System.getProperties();

    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() {
        @Override
        protected PasswordAuthentication getPasswordAuthentication() {
            return new PasswordAuthentication(from, password); //To change body of generated methods, choose Tools | Templates.
        }

    });
    try {
        Message message = new MimeMessage(session);

        message.setFrom(new InternetAddress(from));

        message.setRecipient(Message.RecipientType.TO, new InternetAddress(to));

        message.setSubject(subject);

        message.setText(dataMessage);

        Transport.send(message);

    } catch (Exception e) {
        e.printStackTrace();
    }

}

}

My stack trace is like this....

Severe:   javax.mail.MessagingException: Could not connect to SMTP host: smtp.gmail.com, port: 465, response: -1
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:2042)
at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:697)
at javax.mail.Service.connect(Service.java:386)
at javax.mail.Service.connect(Service.java:245)
at javax.mail.Service.connect(Service.java:194)
at javax.mail.Transport.send0(Transport.java:253)
at javax.mail.Transport.send(Transport.java:124)
at com.suraj.technepbankapplication.SendMail.sendMail(SendMail.java:74)
at com.suraj.technepbankapplication.SendMail.doPost(SendMail.java:41)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:416)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:283)
at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:206)
at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:180)
at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:283)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:200)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:132)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:111)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:536)
at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
at java.lang.Thread.run(Thread.java:745)

Answer 1

After several hours, I solved it by adding

props.put("mail.smtp.user", username);;
props.put("mail.smtp.host", "smtp.gmail.com");
props.put("mail.smtp.port", "465");
props.put("mail.smtp.starttls.enable", "true");
props.put("mail.smtp.debug", "true");
props.put("mail.smtp.auth", "true");
props.put("mail.smtp.socketFactory.port", "465");
props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
    props.put("mail.smtp.socketFactory.fallback", "false");

I also turned the less secure apps on https://www.google.com/settings/security/lesssecureapps

Answer 2

I see the problem in the Properties from gmail. Could you try adding this line to properties:

props.put("mail.smtp.ssl.trust", "smtp.gmail.com");

Answer 3

Change two things in your code

Instead of writing

Properties props = System.getProperties();

change it to

Properties props = new Properties();

Also change

message.setRecipient(Message.RecipientType.TO, new InternetAddress(to));

to

message.setRecipients(Message.RecipientType.TO,
            InternetAddress.parse(to));

This solved your issue in my computer. Give it a try and ping me.