Is it possible to send e-mails with GMail API using user name and password only?

Question

I was told by a colleague that using the Gmail API library, you can send e-mails from corporate Gmail account with user name and password.

So far I could not find out how exactly I can build an instance of the Gmail with user name and password (no access token, no secret).

Is it at all possible to use GMail API for sending e-mails with just user name and password? If so, where can I find an example?

Update 1: When I use the following code

@Test
fun sendMail() {
    val credentials = Properties()
    credentials.load(FileInputStream("src/test/resources/credentials.properties"))

    val username = credentials.getProperty("username")
    val password = credentials.getProperty("password")

    val prop = Properties()
    prop.put("mail.smtp.host", "smtp.gmail.com")
    prop.put("mail.smtp.port", "587")
    prop.put("mail.smtp.auth", "true")
    prop.put("mail.smtp.starttls.enable", "true") //TLS

    val session = Session.getInstance(prop,
            object : javax.mail.Authenticator() {
                override fun getPasswordAuthentication(): PasswordAuthentication {
                    return PasswordAuthentication(username, password)
                }
            })

    try {

        val message = MimeMessage(session)
        message.setFrom(InternetAddress("..."))
        message.setRecipients(
                Message.RecipientType.TO,
                InternetAddress.parse("...")
        )
        message.setSubject("Testing Gmail")
        message.setText("Hello!!")

        Transport.send(message)

        println("Done")

    } catch (e: MessagingException) {
        e.printStackTrace()
    }
}

I get this exception:

javax.mail.AuthenticationFailedException: 535-5.7.8 Username and Password not accepted. Learn more at 535 5.7.8 https://support.google.com/mail/?p=BadCredentials n6sm4681584wmn.48 - gsmtp

Answer 1

Actually, it is not going with gmail api. It's basic mail server configuration for JMS. Here is what i did at spring;

Configuration file:

spring.mail.host=smtp.gmail.com
spring.mail.port=587
spring.mail.username=[GMAIL_USERNAME]
spring.mail.password=[GMAIL_PASSWORD]
spring.mail.properties.mail.smtp.auth=true
spring.mail.properties.mail.smtp.starttls.enable=true
spring.mail.protocol=smtp

Maven dependency:

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

Java code with using JavaMailSender:

@Component
public class EmailService
{
    @Autowired
    protected JavaMailSender emailSender;

    public void sendRegistrationMail(RegistrationForm form) {
        SimpleMailMessage message = new SimpleMailMessage();
        message.setTo(form.getUserMail());
        message.setSubject("-- COOL SUBJECT --");
        message.setText("- COOL TEXT -");
        emailSender.send(message);
    }

}

Source : https://www.baeldung.com/spring-email

Note: make sure if you are planing just try this application, email account allowing less secure apps (Less secure app access). Here is the link you can change that : https://myaccount.google.com/lesssecureapps

Edit: I am adding public version of basic mailsender project - https://github.com/ercinakcay/mailsender-public