Ken Finnigan [Ken Finnigan] - Enterprise Java Microservices

Over the last seven or eight years, the term microservices has exploded in its use, not always to the betterment of developers trying to understand what it means. During the latter part of that time, developers have sought to bring their existing Enterprise Java knowledge to microservices, not always with the best of success. Enterprise Java Microservices is written with the goal of helping existing Enterprise Java developers bridge the gap between traditional application development and microservices.

As part of my job at Red Hat, Ive seen the explosion of microservices first hand. That explosion was a contributing factor in a colleague and me forming the WildFly Swarm project in 2015. We saw the need for developers with existing Enterprise Java knowledge to create microservices, and with nothing focused on the Java EE space at the time, we created WildFly Swarm. Much has changed since then, and the current landscape for microservices makes it seem like a lifetime has passed.

Since I began writing this book, changes have continued to occur rapidly with Enterprise Javain particular, the Thorntail project that I lead, and with microservices more generally. As best as I can, Ive endeavored to update the book as those changes occurred.

It should be noted that this book isnt intended to delve deeply into all aspects of microservice development; it would be many times longer than it is now if that were the case. Where appropriate, links to additional reading are provided if you choose to delve into a particular topic in greater detail.

This book is for any Enterprise Java developer with at least four years of experience. These developers may have basic knowledge of microservices and may even have tried microservices with Node.js or other non-Enterprise Java technologies, but havent learned to develop Enterprise Java microservices.

The book is split into two parts. delves into the nitty gritty of microservice development such as service registries, fault tolerance, and security.

introduces the reader to Enterprise Javain particular, what a monolith is and how it came about. Then the chapter introduces distributed architectures and microservices by covering what they are, what the term means, and other processes that go hand in hand with the switch to microservices. Lastly, it introduces patterns that can be applied to migrating from monoliths to microservices, and when each might apply.

introduces a microservice by developing RESTful endpoints for managing a list of categories for a shopping site. The chapter also introduces the Cayambe monolith, which will be converted to a hybrid and have additional microservices developed for it throughout the book.

introduces the concept of a Just enough Application Server (JeAS) runtime and showcases the differences between the frameworks available to support such a runtime.

covers how unit and integration testing differ now that were developing microservices, and the tools available to make testing easier. The chapter also introduces a new concept of consumer-driven contract testing, which is critical to success in architectures with many microservices collaborating and communicating.

talks about the cloud and the different service models used in different cloud environments. We also discuss cloud native development and how that fits into the microservices world. Next, we use tools at our disposal for local cloud development, and youll see how these tools can be used for testing.