Guide to sending email with JavaMailer using SpringBoot with your GMAIL

Getting Started

Add the Java mail dependency in your pom.xml

  <dependency>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-mail</artifactId>
  </dependency>

Optional but important add the dotenv dependency in your pom.xml

  <dependency>
     <groupId>io.github.cdimascio</groupId>
     <artifactId>dotenv-java</artifactId>
     <version>2.3.1</version>
  </dependency>

Optional but important create a .env file in the project root folder and add the details below in it. Once done, open .gitignore file and add .env (i.e. write .env)
```
  EMAIL_ADDRESS=yourgmail@gmail.com
  PASSWORD=your-password
```

Create a Bean of JavaMailSender (if you choose this option skip no. 5. This is the option i will use) or do add it in your application.properties file (5)

  @Bean
  public JavaMailSender getJavaMailSender() {
     Dotenv dotenv = Dotenv.load(); 
     String email = dotenv.get("EMAIL_ADDRESS"); //you can add your email here if you did not set up .env file
     String password = dotenv.get("PASSWORD");   //you can add your password here if you did not set up .env file

     JavaMailSenderImpl mailSender = new JavaMailSenderImpl();
     mailSender.setHost("smtp.gmail.com");
     mailSender.setPort(587);
     mailSender.setUsername(email);
     mailSender.setPassword(password);

     Properties props = mailSender.getJavaMailProperties();
     props.put("mail.transport.protocol", "smtp");
     props.put("mail.smtp.auth", "true");
     props.put("mail.smtp.starttls.enable", "true");
     props.put("mail.debug", "true");

     return mailSender;
  }

Application.properties file if you do not want to create a Bean of JavaMailerSender

  spring.mail.host=smtp.gmail.com
  spring.mail.port=587
  spring.mail.username=yourgmail@gmail.com
  spring.mail.password=yourpassword@gmail.com
  spring.mail.properties.mail.smtp.auth=true
  spring.mail.properties.mail.smtp.starttls.enable=true

The last step is to send email:

 SimpleMailMessage message = new SimpleMailMessage();
 message.setTo("toemail@email.com");
 message.setSentDate(new Date());
 message.setSubject("Your subject");
 message.setText("Your message body");

 try {
     javaMailSender.send(message);
 } catch (Exception e) {
     System.out.println("ERROR: " + e.getMessage());
 }

If you experience this error:

  https://support.google.com/mail/?p=BadCredentials

This is because Google allows you to generate specific credentials for apps. This is superior to using 'your own' account credentials. This means you will need to enable a two factor verification and create app specific password.
Follow this guide How to Create App-Specific Passwords in Gmail

ikechiU/JavaMailer

Guide to sending email with JavaMailer using SpringBoot with your GMAIL

Getting Started

Reference Documentation