Practical Design Patterns for Java Developers: Hone your software design skills by implementing popular design patterns in Java

Practical Design Patterns for Java is not just a book. It is a gift you can give to your future self or someone you believe in. It is the perfect companion for people new to Java and the JVM, as well as seasoned Java engineers. Unlike most programming language books, this one mixes in the topic of Design Patterns in the context of the Java ecosystem. You can find Java books or ones that teach software design, but having both uniquely intertwined makes this one so unique.What is more, it brought me back to my memories. I first encountered the topic of Design Patterns as a CS student back in the early 2000s. I was at a crossroads, wondering what to do with my life when a Software Engineering course changed my future trajectory forever. While I could write code before that, Patterns made things click on a fundamentally different level. I was now not only seeing code as such but as building blocks that could help me communicate the client's requirements and my solution.So many years after, I am holding Practical Design Patterns for Java Developers and feeling as excited as I was back in that first Software Engineering lecture. Over the years as a Java developer, I have collected a set of techniques I'd rely on but never formally documented them. I believe the same applies to most of the other developers I know of. Thanks to Miroslav's book, we now have a fantastic reference and a teaching tool we can use when onboarding Java engineers in our teams.The Java ecosystem evolves fast, and we may eventually need Part 2 of this book to cover the new additions. In particular, I can see how the recent moves towards better immutability (records, value classes, pattern matching) and concurrency based on Project Loom's green threads will bring new exciting challenges and opportunities. But as we stand right now, Design Patterns for Java Developers is up to the most recent developments in Java.

When I first read the book’s title, I thought, "another book on the good old design patterns,” and wondered why I should bother reading it. But I was wrong; this book gives you far more than a short descriptive compilation of design patterns. It gives you a great introduction to modern Java features and common pitfalls, too; this book is valuable even if you are not interested in design patterns. The author did an excellent job introducing the Java Runtime Environment, with many pointers to other superior reading materials.The chapters on design patterns are also significant: They give a (slightly opinionated) view of all the major design patterns, complete with small examples and examples from the JDK. These chapters feel like an encyclopedia, which I’ll probably revisit occasionally whenever I need to do a more complex architecture.

I’ve been a software developer for most of my adult life. Early in my career, I was in an interview, being asked about design pattern questions. I thought, how hard could that be? Boy, was I in for a surprise; while I’ve coded common design patterns without realizing it, I didn’t know each design pattern had a name.At the time, a mentor showed me the (Gang of Four) Design Patterns book, which helped me re-think the best practices in software architecture and design. However, the book was not written from a Java developer’s perspective. This is precisely why the Practical Design Patterns for Java Developers book resonated with me.Miroslav Wengner (Java Champion) explains how to code design patterns in the Java language properly. For example, the Singleton pattern may sound basic; however, the author explains the importance of the double-checked locking pattern in Java. As many seasoned developers will encounter these pitfalls, this book will help you avoid them.Chapter 1 begins by providing the reader with a great foundation covering object-oriented programming and design principles.Chapter 2 covers much material on the OpenJDK platform (11-17+), many Java language features, and deep knowledge of Java internals.Chapters 3-6 represent the main categories of design patterns such as Creational, Behavioral, Concurrency, etc.Each chapter begins with a URL to the chapter’s source code. I like how Miroslav uses a common theme of automobiles (cars) when showing the code samples. This helps me remember and conceptualize the design patterns tangibly.Each chapter has three main sections Motivation, Finding it in the JDK, and Sample code. The author carefully explains the motivation to help the reader understand the what, where, when & how to apply design patterns in the real world. Next, the author describes where you can find the design pattern in the Java language, such as existing Java types (classes, interfaces, etc.). Thirdly the author presents a UML diagram with sample code. At the end of each chapter, the reader is presented with questions to assess their knowledge.Chapter 7 is my favorite chapter. I love how Miroslav talks about scenarios related to current technology stacks of today, such as microservices, concurrency programming, etc., unlike other pattern books that are too cut and dry for my taste. In practice, we often learn how to do things correctly but don’t realize we’ve been doing some things incorrectly for so long. This chapter will teach you how to recognize Anti-patterns. In other words, how to avoid bad coding (code smell) practices.The Assessments chapter (like at the end of each chapter) will provide many questions to help challenge the reader. If only I could turn back time and use this book during those intense interviews.Pros:- UML diagrams- Easy examples to follow- Explains Anti-Patterns- Assessments in each chapter to challenge the reader- References to further reading sections- Code is open-sourced on GitHub- Practical examplesCons:- Not for the Java beginnerIf you are an impatient mid to senior-level Java developer, you can just go jump to Chapter 3.- The title font of each design pattern name isn’t prominent at first glance.ConclusionThe book is a breath of fresh air for many Java developers who care about maintaining, developing, and designing software. You can immediately tell Miroslav has a deep knowledge of the Java Platform internals. Many examples are easy to follow and well-explained. This is the kind of book you can read during your travels without needing your computer and compiler. It may not be as thrilling as a mystery novel, but you never know; it could land you your next dream job.

As a fellow Java Champion, I can wholeheartedly recommend Practical Design Patterns for Java Developers. This book offers a fresh perspective on design patterns and provides valuable insights for both beginners and professionals with years of experience.I liked that the book is organized into three main parts: An into to Design Patterns and Java Platform Functionalities, followed by tips for Implementing Standard Design Patterns, then covers additional Essential Patterns and Anti-Patterns.After a great intro, the second part covers several types of design patterns, each illustrated with clear, practical usage examples, and instances found in the JDK. This approach allows developers to quickly grasp the real-world applications and advantages of utilizing design patterns effectively.The third part of the book focuses on concurrency design patterns and common anti-patterns. I especially appreciated the coverage of anti-patterns, particularly relevant in the context of today's multi-core and multi-threaded computing environments. Miroslav's in-depth exploration of these patterns demonstrates how they contribute to more efficient and robust applications.What sets this book apart is the personal touch Miroslav brings to the material. His clear and concise writing style, combined with his expertise and passion for Java an patterns makes the book enjoyable to read. It's evident that he has put a lot of thought into organizing the content and providing useful code samples, further reading suggestions, and assessments to reinforce the concepts covered.Practical Design Patterns for Java Developers is a must-read for experienced Java developers who want to sharpen their software design skills and stay up-to-date with the latest trends in the field. Miroslav's expertise, combined with his unique perspective, makes this book an invaluable resource for creating more efficient, maintainable, and scalable Java applications.

It is remarkable book with clear explanations of design patterns and many useful examples including references to JDK.One of the standout features is chapter about concurrency design patterns, which helps to understand Java concurrency functionality better.I also appreciated the author's attention to best practices and common anti-patterns.Overall it is easy to read, cohesive guide to design patterns from the latest Java version prospective.