MailSender | Mail Sender use Background Task

Got it..After researching alot on the internet, i was able to get the issue fixed. Below import and inputs i had to include to make it work successfully. Adding here so that if other face same issue, they can have a look at this to fix the issue.

I have created application-dev.properties and application-prod.properties from the actual application.properties

This is already very good (except the exposing secrets in git part...), and you are in fact done!

To activate/override them, you just need to set spring.profiles.active on the according environment.

This can be done trough one of the 14(!) spring-boot defined property sources in Chapter 2, Externalized Configuration, e.g.:

• (java.lang.)System property (6.):

Create a PaymentService class which should contain the method getTotalPayment. Inject this class in EmailSend (tip: please change this class name from EmailSend to EmailSender as class names should be noun) class. And then in PaymentService Class you should interact Data Repository class. Call this getTotalPayment method from the EmailSend class.

This is expected behaviour because:

multiple tabs/instances of the same browser will usually share the same server-side session when interacting with the same domain.

means that you can´t be logged in with different users in different tabs per default.

And I don´t think that you would want this, just think of the downsides, do you really want to login again for every tab? This is very uncommon practice. Imagine you would open a stack-overflow question in a new tab and you would not be logged in there.

There are ways to achieve this though, but really re-think if thats your actual usecase, i don´t think so, you are just developing your feature and testing it, and in production a new user will not be already logged in as admin is my assumption.

So for testing your feature just use a private tab (that does usually not share the same server-side session )

if you want to learn more i found this pretty cool so-thread where users try to explain as best as possible What are sessions? How do they work?

As you can read on the API docs from Spring, you should use a different class: "Consider JavaMailSender and JavaMail MimeMessages for creating more sophisticated messages, for example messages with attachments, special character encodings, or personal names that accompany mail addresses."

I resolved my issue by changing the HTTP request pipeline order as follows:

Based on the error message, remove the JavaMailSender constructor argument in the NotificationService constructor (assuming you are not using that in the NotificationService).

In case you wanted to use the JavaMailSender in the NotificationService, you would need to create a Bean of type JavaMailSender which can be injected in the NotificationService. For AWS-SES, you can do so by defining the following bean in your configuration.

This is a recent protection from Gmail to prevent email phishing attacks

Because links to malicious websites can be sent in emails, Google adds link protection for all official Gmail clients (web, Android, and iPhone & iPad). Some of these protections are now available for some users that use a third-party email application (IMAP client).

For these users, clicking a link in a recent message starts a malicious link check. If nothing malicious is detected, the user is taken to the destination. For older messages, a window might appear, requiring a tap or click to open the link.

Source: https://support.google.com/mail/answer/10173182?hl=en#zippy=%2Cwhich-third-party-email-applications-have-these-new-protections

I would recommend client to use latest email client or use some third-party SMPT servers that does not have this protection. Remember, using random third-party SMTP providers might be risky.

I have personally used, sparkpost.com and mailgun.com. Both were pretty good and had some developer plans for free emails. If I remember correctly, sparkpost.com provides SMTP access too.

My interpretation after stepping through the code is that SMTPConnection.quitCloseConnection is missing a call for closing the actuall connection.

So QUIT is sent, then the smtp-server sends connection reset since the connection is not closed.

I created an issue in vert.x mail client.