Congratulations on completing this chapter, where the skills and knowledge required to build an asynchronous, scalable Email Formatter application were discussed.

This chapter showed you how to use Spring Data JPA for creating entities and repositories to store data in a relational database management system (RDBMS). An in-memory database named H2 was used for demonstration.

Next, we explained how to use Apache FreeMarker to format emails by replacing placeholders with actual values and generating HTML content dynamically.

Furthermore, we explained how to write producers and consumers for Apache Kafka using Spring Kafka library. Spring Kafka does a lot of the heavy lifting with auto-configuration so that it is easier to develop. 

We explained how to use Spring Web MVC REST controllers to accept reset password requests from users and also how to protect endpoints using Spring Security form-based authentication and authorization.

Subsequently, this chapter talked about Java Mail and how to use it to send emails from the Email Formatter consumer.

Eventually, this chapter talked about how to run ZooKeeper and Apache Kafka, and then demonstrated the use of the Email Formatter consumer and the User Registration microservice to accept reset password requests from users, queue the Apache Kafka topic and format, and send emails via consumers. This concludes an exciting learning journey of Spring Boot 2.0 with hands-on examples. Hopefully, this book provided a greater deal of understanding of Spring Boot, Spring Boot 2.0, Spring Web Flux, Spring Security, Spring Data JPA, Spring Data MongoDB, Spring Data Redis and many more frameworks. Happy learning!