Witamy Was gorąco w Nowym Roku i życzymy samych słonecznych dni! Na dobry początek proponujemy zapoznać się z recenzją książki Java 8 Lambdas. Autorem książki jest Richard Warburton, autorem recenzji – Sebastian Łaskawiec. To druga recenzja na koncie Sebastiana i jednocześnie szósta na koncie wszystkich naszych JUGowiczów.


Java 8 Lambdas: Functional Programming for the Masses

If you’re a developer with core Java SE skills, this hands-on book takes you through the language changes in Java 8 triggered by the addition of lambda expressions. You’ll learn through code examples, exercises, and fluid explanations how these anonymous functions will help you write simple, clean, library-level code that solves business problems.

Lambda expressions are a fairly simple change to Java, and the first part of the book shows you how to use them properly. Later chapters show you how lambda functions help you improve performance with parallelism, write simpler concurrent code, and model your domain more accurately, including building better DSLs.


Richard Warburton is an empirical technologist and solver of deep-dive technical problems. He has professionally worked on static analysis problems, verifying part of a  compiler and developing advanced automated bug detection technology. More recently his career has been focussed on data analytics for high performance computing. He is a leader in the London Java Community, sits on their JCP Committee and organises the Adopt-a-JSR programs for Lambdas and Date and Time in Java 8. Richard is also a known conference speaker, having talked at JavaOne, DevoxxUK and JAX London. He obtained a PhD in Computer Science from The University of Warwick where his research focussed on compiler theory.



The book describes practical approach to new features introduced in Java 8. Most of the book is dedicated to Lambdas but the author also described other language and library add-ons.

The first two paragraphs contain introduction to Lambda expressions and explain why Java needs them. Third paragraph presents Stream’s key concepts. All operations (like map, filter or flatMap) are explained using very descriptive examples. Fourth paragraph goes into the details of other Java 8 concepts like Optional, default/static methods in the interfaces and binary compatibility. After introducing those additional concepts the author goes into the details of collections and Collectors (starting from easy topics like element ordering and finishing on advanced like parallelism vs concurrency, debugging or refactoring). The last two paragraphs of the book describes architectural design patterns using Lambda expressions and shows some real life examples for topics like nonblocking I/O.

Writing style

Java 8 Lambdas is written using very easy to learn style. All concepts are briefly described theoretically and explained in detail using examples. There is also a GitHub repository with exercises for presented topics. The author focuses on practical approach for Java 8 features rather than theoretical aspects.

Conclusion and recommendation

Java 8 Lambdas is a must-have book for those who start using new features introduced in Java 8. The author clearly assumes basic understanding of previous Java features, so I wouldn’t recommend this book for beginners. On the other hand an experienced programmer will feel comfortable with key concepts of Lambdas after reading less then forty pages (!!).

I highly recommend reading this book in two parts. At first, read basic concepts and get familiar with them (paragraphs 1-4). Do some exercises or ever better - get involved into some project which uses Java 8. Finally, finish reading the advanced topics of the book.

Rating: 5/5


Sebastian Łaskawiec

Senior Software Developer in Red Hat interested in JEE containers and Caching technologies who spends most of his free time on home brewing, ice skating or skiing.

Szukamy kolejnych odważnych

Jeśli ktoś z Was chciałby otrzymać kopię wybranej przez siebie książki w zamian za jej recenzję, to zapraszamy do odpowiedniego wątku na naszej grupie dyskusyjnej. Dzięki partnerstwu z wydawnictwami Manning Publications Co., O’Reilly Media oraz Packt Publishing macie do wyboru bardzo szeroki wachlarz książek o różnorodnej tematyce.