Architecting Modern Java EE Applications

4.4 (18 reviews total)
By Sebastian Daschner
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  1. Introduction

About 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.

Publication date:
October 2017


Chapter 1. Introduction

Compared to the past, we see a lot of new demands in enterprise software. It is no longer sufficient to just develop some piece of software and deploy it to an application server. Or maybe it never was.


New demands in enterprise systems

The world moves faster than ever. And moving fast is one of the most important criteria of today's IT companies. We see companies that can adapt to the real world and the customer's needs with high velocity. The expected time to market of features has shrunk from years and months to weeks and less. In order to cope with this, companies not only need to introduce new technology or throw more money at their business problem, but also rethink and refactor the way they operate at the core of their IT.

What does move fast mean in this context? What aspect does this include? And which methods and technology support this?

Moving fast is all about quickly adapting to the needs of the market and customers. If a new feature is desired or looks promising, how long does it take to get from the initial idea to the feature being in the user's hands? If new infrastructure is required, how long does it take from that decision to the running hardware? And do not forget, if a certain piece of software is developed with all that velocity, is there automated quality control in place that ensures everything will work as expected and not break the existing functionality?

In software development, most of these questions lead to Continuous Delivery and automation. Software that is being developed needs to be built, tested, and shipped in an automated, fast, reliable, and reproducible way. A reliable, automated process not only leads to quicker turnarounds but ultimately higher quality. Automated quality control, such as software tests, are part of the process. In modern software development, Continuous Delivery, automation, and proper testing are some of the most important principles.

Traditionally, infrastructure was a big bottleneck in most companies. Smaller companies often struggled to provide new infrastructure with a limited budget. Bigger companies mostly fail to implement fast and productive processes. For big corporations, in most of the cases the issue is not the budget but the implementation of the processes. It is not untypical to wait days and weeks for new infrastructure, due to approvals and overly complex processes that technically could have been finished in a matter of minutes.

Therefore, application infrastructure and how it is designed is an important aspect. Chapter 5, Container and Cloud Environments with Java EE, will show you the topic of modern cloud environments. Actually, we will see that it's not so much about whether cloud service providers are being used. Fast and productive processes certainly can be implemented with on-premises hardware. Rather, it is more a question of whether processes are implemented properly, using well-suited technologies.

Modern infrastructure needs to be set up in a matter of minutes, in an automated, fast, reproducible, and reliable way. It should adapt to changing demands without great effort. To meet this criterion, infrastructure should be defined as code, either with procedural scripts or in declarative descriptors. We will see how infrastructure as code impacts software development workflows and which technologies support it.

These demands will impact the way teams operate. It is no longer sufficient for development teams to just develop and let the operational teams deal with running the software and facing potential issues on production. This practice always leads to tensions and finger pointing once critical errors occurred in production. Instead, the common goal should be to deliver software that fulfills a purpose. By defining the required infrastructure and configuration as code, development and operations teams will naturally move together. This DevOps movement, a compound of development and operations, aims toward accountability of the software team as a whole. Everybody involved is responsible for customers being able to use proper software. This is more an organizational challenge than a technical one.

On a technical aspect, Continuous Delivery, as well as the 12-factor and cloud nativebuzzwords attempted to meet these demands. The 12-factor and cloud native approaches describe how modern enterprise applications should be developed. They define requirements, not only for the development processes but also for the way applications are run. We will look into these approaches, modern cloud environments, and where Java EE supports us, later in this book.


Modern way of realizing enterprise systems

Now we will look at how enterprise software projects are being developed.

Following the approach of meeting the needs of real-world customers, we will face the question of the purpose of the application that we want to develop. The motivations and purposes of the enterprise systems need to be clear before immediately going into technology details. Otherwise, software is just being developed for the sake of developing software. Sadly, this is the case way too often. By focusing on business logic and the principles of Domain-Driven Design, as wonderfully described in the book by Eric Evans, we will ensure that the software we are building will meet the business demands.

Only after the application's purpose and responsibility is clear to the stakeholders, can we focus on the technological aspects. Teams should favor technologies that can not only implement the business use cases appropriately but also reduce the amount of work and overhead. Developers should be able to focus on the business, not the framework and technology. Good frameworks support solving business problems in a lean way and don't want the developer's attention themselves.

The chosen technology should also support productive development workflows as much as possible. This not only includes automation and fast development turnarounds but also the ability to embrace modern infrastructure, such as Linux containers. In Chapter 4, Lightweight Java EE, and Chapter 5, Container and Cloud Environments with Java EE, we will have a closer look into the nuts and bolts of modern environments and how Java EE supports them.


Relevance of Java EE in modern systems

Let's talk about Java EE since this is the topic of this book and it is relevant in enterprise systems.

Java EE and J2EE are being used heavily, especially in bigger companies. One of the advantages was always that the platform consists of standards that guarantee to be backwards compatible with older versions. Even old J2EE applications are guaranteed to still function in the future. This was always a big benefit for companies that are planning for the long term. Applications that are developed against the Java EE API can run on all Java EE application servers. Vendor-independent applications enable companies to build future-proof software that doesn't lock it into a specific solution. This turned out to be a sound decision that ultimately led to a mindset of the enterprise industry that standards, or de facto standards which everybody agrees upon, improve the overall situation.

Compared to the J2EE world, a lot has changed in Java EE. The programming model is totally different, much leaner, and more productive. This was drastically changed when the name switched from J2EE to Java EE 5, and especially since EE 6. We will have a look at the modern way of developing Java enterprise in Chapter 3, Implementing Modern Java Enterprise Applications. We will see what architectural approaches and programming models are being used and how the platform leverages development productivity much more than in the past. Hopefully, the idea of why Java EE now provides a modern solution to develop enterprise applications will become clear.

Right now, bringing this message out to the industry is actually more of a marketing and political challenge than a technical one. We still see tons of developers and architects who still consider Java EE to be the cumbersome, heavyweight enterprise solution of the J2EE age, which required a lot of time, effort, and XML. Enterprise JavaBeans (EJB), as well as application servers, have a particularly bad reputation due to their past. This is why a lot of engineers are biased toward that technology. Compared to other enterprise solutions, Java EE never saw much marketing targeted at developers.

In Chapter 4, Lightweight Java EE, we will see why modern Java EE is actually one of the most lightweight enterprise solutions. We will define the term lightweight aspects and see why the Java EE platform is more relevant than ever, especially in modern cloud and container environments. The impression the IT industry has of a particular technology is important for its success. I hope this chapter will shed some light into this topic.

Companies have usually chosen Java EE mostly because of its reliability and backwards compatibility. I personally favor Java EE because of its productivity and ease of use. In Chapter 4, Lightweight Java EE, and Chapter 5, Container and Cloud Environments with Java EE, we will cover more about this. In this book, I would like to show the readers why Java EE is a solution well-suited to today's enterprise demands. I will also show the technologies and standards, not in every detail, but rather how they are integrated with each other. I believe that focusing on the integrational part leads to a better understanding in how to effectively craft enterprise applications.


Java EE 8 update and roadmap

Let's have a very high-level overview of what has happened in Java EE version 8. The goal of this version is to improve the developer's experience even more, to streamline the API usage further, and to make Java EE ready for new demands in cloud environments. We saw two completely new JSRs, JSON-B (Java API for JSON Binding) and Security, together with improvements in existing standards. In particular, introducing JSON-B simplifies the integration of JSON HTTP APIs in a vendor-independent way.

The direction of Java EE is to improve the development of enterprise applications in regard to modern environments and circumstances. It turns out that modern environments are not only compatible with Java EE but encourage approaches that have been part of the platform for years. Examples are the separation of the API from the implementation, or application server monitoring.

On the long-term roadmap, there is better support for modern monitoring, health-checks, and resilience. Currently, these aspects have to be integrated in a few lines of codes, as we will see in later chapters. The long-term goal is to make that integration more straightforward. Java EE aims to let developers focus on what they should focus on - solving business problems.


Java Community Process

What makes Java EE platform unique is the process of how it is specified. The standards of Java EE are developed as part of the Java Community Process (JCP). The JCP is a prime example of an industry that actively encourages participation in defining standards, not only from the few engineers involved but anybody interested in that technology. The platform comprises standards in the form of Java Specification Requests (JSR). These JSRs are not only relevant for Java and Java EE but also for technologies that build upon them, such as the Spring framework. Ultimately, the real world experience of these other technologies then again help shaping new JSRs.

During application development, and especially when encountering potential issues, the written specifications that emerge from the JSRs are extremely beneficial. The vendors who support the enterprise platform are required to provide the implementation in the way it's specified in these standards. That said, the specification documents inform both the vendors and developers as to how the technology will work. If some functionality is not met, the vendors are required to fix these issues in their implementations. This also means that developers, in theory, only have to learn and know these technologies, no vendor-specific details.

Every developer can participate in the Java Community Process to help in shaping the future of Java and Java EE. The Expert Groups who define the specific standards welcome constructive feedback from anybody interested in the topic, even if they're not active members of the JCP. Other than this, you're able to have a peek into the next versions of the standards even before they're released. These two facts are very interesting for architects and companies. There is not only insight into where the direction will go but also the possibility to contribute and make an impact.

These motivations were also two of the reasons why I personally specialized in Java EE. I have a background of enterprise development with the Spring framework. Besides the fact that both technologies are very similar in terms of the programming model, I especially valued the power of the CDI standard as well as the possibility to seamlessly use all of the technologies within the platform. I started to look into the specific JSRs that are part of the enterprise platform and started to contribute and provide feedback on features that were standardized back then. At the time of writing this book, I'm part of two Expert Groups, JAX-RS 2.1 and JSON-P 1.1. Helping to define these standards improved my knowledge in enterprise systems a lot. You are naturally obliged to dive deep into the topics, motivations, and solutions of the specific technology that you help standardize. And of course, it is somewhat satisfying to know that you helped in working on standards in the IT industry. I can only encourage developers to participate in the JCP, looking into what's currently developed, and to contribute and provide feedback to the Expert Groups.


What to expect in the book

I've decided to write this book about the things I learned in the past working on Java enterprise systems of all kinds. My motivation is to show you what a modern Java EE approach looks like. This, of course, first of all aims toward developing enterprise applications themselves, and modern programming models. I try to build up an impression as to how Java EE is used in the age of EE 8 and where the platform shines. There are new design patterns and paradigms being used that have emerged from modern framework approaches. If you were familiar with the J2EE world, you will hopefully see the advantage of modern Java EE. I try to show which of the old paradigms, constraints, and considerations that made J2EE sometimes being disliked among developers are not true anymore and can be discarded. Besides this, the book is an attempt to spread some enthusiasm and explain why I am convinced that Java Enterprise serves the purpose of realizing enterprise applications well.

That said, you, the reader, don't need prior knowledge of the J2EE world and patterns and best practices thereof. In particular, the programming model so different that I'm convinced it makes sense to showcase today's approach from a green field.

It you have built and designed J2EE applications, this is great. You will see what the challenges with past J2EE design patterns were, particularly when in the modern world, our domain can focus on business demands first and not the technology used to implement it. This is especially true when we follow the approaches of Domain-Driven Design. You will notice how many cumbersome and painful aspects of J2EE systems in the past can be eradicated in modern Java EE. The simplicity and power of the Java EE platform may inspire you to rethink certain approaches that we have done so far. Maybe you can try to take a mental step back to have a fresh, unbiased view on the technology.

This book is meant for software engineers, developers and architects who design and build enterprise applications. In the book, I will mostly use the term developers or engineers. That said, I am convinced that architects should also, from time to time, the more the better, touch source code and get their hands dirty with technology. This is not only to support other developers in the team but also important for themselves to get more real-world experience. In the same way all developers should have at least a basic understanding of the system's architecture and the reasoning for the architectural choices. Again, the better this mutual understanding is, the better will the communication and development function in the projects.

Modern enterprise application development touches much more than just the sole development. As we are seeing, new demands of enterprise applications, engineers care about development workflows, cloud environments, containers, and container orchestration frameworks. We will cover whether and how Java Enterprise fits into this world and what approaches and best practices there are that support this. This will tackle the topics of Continuous Delivery and automated testing, why they have such importance, and how they integrate with Java EE. We will also cover container technologies, such as Docker, and orchestration frameworks such as Kubernetes. In today's enterprise world it's important to show how a technology such as Java EE supports these areas.

Microservice architecture is a big topic, another of today's hypes. We will look at what microservices are about, and if and how they can be realized with Java EE. The topics of security, logging, performance, and monitoring will also be covered later in this book. I will point out what architects should know and be aware of in today's enterprise software world. The used choices of technology, especially when it comes to modern solutions that support applications; for example, in the areas of 12-factor or cloud native applications, serve as examples as to what would be chosen as of today. However, it is much more important to understand what the concepts and motivations behind these technologies are. Used technology changes day by day, principles and concepts or computer science live much longer.

For all of the subjects that I cover in this book, my approach is to show the motivations and reasoning behind solutions first, and then how they are applied and implemented in Java EE second. I believe that simply teaching a certain technology may certainly help developers in their daily jobs but they will not fully embrace the solution until the motivations behind it are completely understood. This is why I will also start with the motivations behind enterprise applications in general.

There is a lot of functionality included in Java EE, even more if you look into the past. This book does not aim to represent a full Java EE reference work. Rather, it is intended to provide real world experience as well as recommendations, call them best practices, tackling typical scenarios with pragmatic solutions. Now, please lean back and enjoy the journey through a modern enterprise software world.


About the Author

  • Sebastian Daschner

    Sebastian Daschner is a self-employed Java consultant, author, and trainer and is enthusiastic about programming and Java (EE). He participates in the JCP, helping to form the future standards of Java EE, serves in the JSR 370 and 374 Expert Groups, and collaborates on various open source projects. For his contributions in the Java community and ecosystem, he was recognized as a Java Champion, Oracle Developer Champion, and double 2016 JavaOne Rockstar. He has been working with enterprise Java for more than 8 years. Besides Java, Sebastian is also a heavy user of Linux and container technologies such as Docker. He evangelizes computer science practices on, in his Newsletter, and on Twitter via @DaschnerS. When not working with Java, he also loves to travel the world—either by plane or motorbike.

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Latest Reviews

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Excellent content just what I was looking for
Simple overview on building Java EE apps in general.

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