Como enviar e-mail via Java

package mailsender;

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

public class Main {

 public static void main(String[] args) throws Exception {    
    String smtpHost = "";
    String smptPort = "";
    String smtpUser = "";
    String smtpPassword = "";
    MailSender ms = new MailSender(smtpHost, smtpPort, smtpUser, smtpPassword);
    ms.send("diego.ziquinatti@ecore.com.br", "Hello", "Testando email");
  
    System.out.println("Enviado com sucesso!");
 }

 static class MailSender {

    private String smtpHost;
    private String smtpPort;    
    private PopupAuthenticator authenticator;

    public MailSender(String smtpHost, String smtpPort, String smtpUser, String smtpPassword) {
       this.smtpHost = smtpHost;
       this.smtpPort = smtpPort;
       authenticator = new PopupAuthenticator(smtpUser, smtpPassword);
    }

    public void send(String to, String subject, String content) throws AddressException, MessagingException {
       // Create a mail session
       java.util.Properties props = new java.util.Properties();
       props.put("mail.smtp.host", smtpHost);
       props.put("mail.smtp.port", smtpPort);
       props.put("mail.smtp.auth", "true");
       props.put("mail.smtp.user", "login");
       props.put("mail.smtp.password", "password");              

       // Create the session object
       Session session = Session.getDefaultInstance(props, authenticator);       

       // Construct the message
       Message msg = new MimeMessage(session);       
       msg.setFrom(new InternetAddress(authenticator.getUser()));
       msg.setRecipient(Message.RecipientType.TO, new InternetAddress(to));
       msg.setSubject(subject);
       msg.setText(content);

       // Send the message
       Transport.send(msg);
    }
 }

 static class PopupAuthenticator extends Authenticator {
  
    private String user;
    private String password;
  
    public PopupAuthenticator(String user, String password) {
       this.user = user;
       this.password = password;
    }
  
    @Override
    public PasswordAuthentication getPasswordAuthentication() {
       return new PasswordAuthentication(getUser(), getPassword());
    }

    public String getUser() {
       return user;
    }

    public String getPassword() {
       return password;
    }
 }
}