Book Image

Architecting Modern Java EE Applications

By : Sebastian Daschner
Book Image

Architecting Modern Java EE Applications

By: Sebastian Daschner

Overview of this book

Java EE 8 brings with it a load of features, mainly targeting newer architectures such as microservices, modernized security APIs, and cloud deployments. This book will teach you to design and develop modern, business-oriented applications using Java EE 8. It shows how to structure systems and applications, and how design patterns and Domain Driven Design aspects are realized in the age of Java EE 8. You will learn about the concepts and principles behind Java EE applications, and how to effect communication, persistence, technical and cross-cutting concerns, and asynchronous behavior. This book covers Continuous Delivery, DevOps, infrastructure-as-code, containers, container orchestration technologies, such as Docker and Kubernetes, and why and especially how Java EE fits into this world. It also covers the requirements behind containerized, zero-dependency applications and how modern Java EE application servers support these approaches. You will also learn about automated, fast, and reliable software tests, in different test levels, scopes, and test technologies. This book covers the prerequisites and challenges of distributed systems that lead to microservice, shared-nothing architectures. The challenges and solutions of consistency versus scalability will further lead us to event sourcing, event-driven architectures, and the CQRS principle. This book also includes the nuts and bolts of application performance as well as how to realize resilience, logging, monitoring and tracing in a modern enterprise world. Last but not least the demands of securing enterprise systems are covered. By the end, you will understand the ins and outs of Java EE so that you can make critical design decisions that not only live up to, but also surpass your clients' expectations.
Table of Contents (22 chapters)
Title Page
Credits
Foreword
About the Author
Acknowledgments
About the Reviewer
www.PacktPub.com
Customer Feedback
Dedication
Preface
12
Appendix: Links and further resources

Communication


Building CQRS systems is one approach to realizing asynchronous, eventually consistent communication. As we have seen previously in this book, there are many forms of communication, synchronous as well as asynchronous.

In order to enable scalable applications, distributed systems should not rely on synchronous communication that involves several systems. This leads to distributed transactions.

One approach to realize scalability with technology-agnostic, synchronous communication protocols is to model logically asynchronous processes. For example, communication protocols such as HTTP can be used to trigger processing that happens asynchronously while the caller immediately returns. This introduces eventual consistency, but enables the system to scale.

This also involves the consideration of whether the applications that made the distributed system make a difference in system-internal, and external communication. CQRS uses this approach by offering external interfaces, for example...