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Kotlin in Action
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Kotlin is a new programming language targeting the Java platform. It offers on expressiveness and safety without compromising simplicity, seamless interoperability with existing Java code, and great tooling support. Because Kotlin generates regular Java bytecode and works together with existing Java libraries and frameworks, it can be used almost everywhere where Java is u
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ebook, Manning Publications, 360 pages
Published
May 2016
by Manning Publications
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Very complete, focused on its differences compared to other languages not just in terms of syntax but also in terms of patterns. Because it was written by one of the designers of the language is very useful because he explains the decisions they made and you can understand the "why"s.
In the Generics chapter, there is the better explanation I ever read about invariants, covariants, and contravariants.
DSL chapter is very useful to understand how the majority of Kotlin libs work. It is much better ...more
In the Generics chapter, there is the better explanation I ever read about invariants, covariants, and contravariants.
DSL chapter is very useful to understand how the majority of Kotlin libs work. It is much better ...more

I don't like the book. It keeps saying Java is bad. I was trained in Java and I don't think the authors are making the right points. Java is a great language in my opinion, while Kotlin looks more like a bunch of ad hoc ideas. It's less elegant than Java. But the fact is that my colleagues are using Kotlin and I have to learn it. I'm looking for a better book that shows basic respect for Java.
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Dec 18, 2019
Nickson Kaigi
rated it
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review of another edition
Shelves:
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computer-science
* 3.5 stars
* Must Have, if you intend to pass the Coursera course: Kotlin for Java Developers.
* This book was written in 2017 for Kotlin 1.0. When I read it, Kotlin was in version 1.3. Still a good book.
Exactly what you would expect from the people who worked at JetBrains to develop the Kotlin language.
Not beginner friendly, but goes in-depth with the language features. Has excellent comparisons between how Java does things vs the Kotlin way.
Loved reading part 2 of the book: Embracing Kotlin. Th ...more
* Must Have, if you intend to pass the Coursera course: Kotlin for Java Developers.
* This book was written in 2017 for Kotlin 1.0. When I read it, Kotlin was in version 1.3. Still a good book.
Exactly what you would expect from the people who worked at JetBrains to develop the Kotlin language.
Not beginner friendly, but goes in-depth with the language features. Has excellent comparisons between how Java does things vs the Kotlin way.
Loved reading part 2 of the book: Embracing Kotlin. Th ...more

I really enjoyed the way the book is written.
The authors found out a way to present the cool Kotlin features to make them easy to grasp.
The only thing that I found out quite hard to keep the pace with was the last part in the kotlin reflection (json parsing and object deserialization).
I am already looking forward to seeing the 2nd version of Kotlin in Action - including probably the kotlin coroutines, KJS.
The authors found out a way to present the cool Kotlin features to make them easy to grasp.
The only thing that I found out quite hard to keep the pace with was the last part in the kotlin reflection (json parsing and object deserialization).
I am already looking forward to seeing the 2nd version of Kotlin in Action - including probably the kotlin coroutines, KJS.

This should be your first Kotlin book provided you have a good grasp programming concepts.
It is a brisk, no-nonsense, and pretty exhaustive coverage of the features of Kotlin. Unlike programming books that introduce a new language, this book does not go over the basics concepts of OO. Instead, it assumes you know your programming concepts (at least OO) and starts by describing how they are supported in Kotlin. For concepts common to Java, the book 1) briskly describes the concept as it occurs i ...more
It is a brisk, no-nonsense, and pretty exhaustive coverage of the features of Kotlin. Unlike programming books that introduce a new language, this book does not go over the basics concepts of OO. Instead, it assumes you know your programming concepts (at least OO) and starts by describing how they are supported in Kotlin. For concepts common to Java, the book 1) briskly describes the concept as it occurs i ...more

The book teaches Kotlin from the perspective of a skilled Java programmer.
It clearly separates topics into chapters but language aspects are often described insofar as they differ from Java.
Explanations are clear and generally easy to follow.
It cannot be used as a reference.
The book also pays a lot of attention to Java compatibility.
When Kotlin language features are explained the authors always indicate how Kotlin compiles those features into Java bytecode and how Java code can access code compi ...more
It clearly separates topics into chapters but language aspects are often described insofar as they differ from Java.
Explanations are clear and generally easy to follow.
It cannot be used as a reference.
The book also pays a lot of attention to Java compatibility.
When Kotlin language features are explained the authors always indicate how Kotlin compiles those features into Java bytecode and how Java code can access code compi ...more

Loved it. I’ve worked with Java and Groovy for years and some time ago started Kotlin. Book gave me insights into concepts that I kind of used but did not understand them thoroughly.
Useful bits for me:
- objects are for singleton use
- extension functions are a thing, the ones with receiver types are useful in DSLs, also extension functions can be defined inside of a class
- generics, variance - now its clear what those “in” an “out” next to generic types mean
- operator overloading is something I’d ...more
Useful bits for me:
- objects are for singleton use
- extension functions are a thing, the ones with receiver types are useful in DSLs, also extension functions can be defined inside of a class
- generics, variance - now its clear what those “in” an “out” next to generic types mean
- operator overloading is something I’d ...more

Very no-nonsense and straightforward presentation style tailored for experienced programmers. I didn't feel like I have to skip through most of the book. It really focused on introducing new JVM language instead of teaching programming.
I liked how it took the time to explain a few implementation details, so that the reader could immediately understand how various language features interact with Java. But the authors didn't stop at that and also included some notes on how performance may be affec ...more
I liked how it took the time to explain a few implementation details, so that the reader could immediately understand how various language features interact with Java. But the authors didn't stop at that and also included some notes on how performance may be affec ...more

An excellent book for developers to know more about Kotlin. It assumes some Java experience for the readers. If you haven't already known some Kotlin before, I'd say this book is perfect for you to get started.
I already knew some Kotlin and would like to delve more into the advanced topics. So I skimmed through the first half of the book which is the foundations and focused on the second half explaining the type system, lambda, DSL, reflections of Kotlin.
Overall I found the author explaining wit ...more
I already knew some Kotlin and would like to delve more into the advanced topics. So I skimmed through the first half of the book which is the foundations and focused on the second half explaining the type system, lambda, DSL, reflections of Kotlin.
Overall I found the author explaining wit ...more

This is a perfect book to read, if you want to start with Kotlin, all the main features are explained here. As said in the back cover, the authors are expecting you to have experience with Java, it is true, so if you only starting you programming career, this book wouldn't be a smooth read for you. There is no doubt that it will boost your performance if you're only starting with kotlin, so I really recommend it to read before you start some serious complex stuff with this language.
I really than ...more
I really than ...more

This is the perfect book to learn Kotlin (if you have already experience programming, of course)
It's a trip to understand almost all the features kotlin has, inciting not only in the well know features like nullability or Higher order functions, also in the core parts of kotlin and, more important, in the whys and hows.
With this book you have also access to a complete set of exercices and examples similar to Kotlin Koans.
If you are planing to develop in Kotlin this is your book.
...more
It's a trip to understand almost all the features kotlin has, inciting not only in the well know features like nullability or Higher order functions, also in the core parts of kotlin and, more important, in the whys and hows.
With this book you have also access to a complete set of exercices and examples similar to Kotlin Koans.
If you are planing to develop in Kotlin this is your book.
...more

This is a great book to learn Kotlin if you already know Java. If you do not know Java, many things will probably be confusing. The books starts off with the basics and works its way towards more advanced topics.
Also, it is a lot to take in from one reading. Myself, I expect to re-read this book.
Also, it is a lot to take in from one reading. Myself, I expect to re-read this book.

Excellent overview of the Kotlin programming language. Starts with the fundamentals and works up to higher level constructs at a great pace. I found the chapter on DSLs most useful. It illustrates the power of lambdas with receivers and extension functions and should further help you understand Kotlin DSLs in the wild.

As the book states, it will work the best for those who want to see Kotlin features and move from other JVM-based languages like Java.
I definitely recommend it for people who consider switching to Kotlin but beware that it is not easy and relaxed reading. I found it hard to understand some ideas the way they described here.
I definitely recommend it for people who consider switching to Kotlin but beware that it is not easy and relaxed reading. I found it hard to understand some ideas the way they described here.

Excellent book to get into Kotlin essentials. Please note this is not a hands-on book that guides you through the language using exercises and examples. Mostly of the contents are theory on the
Logical programming of Kotlin (authors are part of team behind JetBrains).
Good resource as a jumpstart from Java to Kotlin.
Logical programming of Kotlin (authors are part of team behind JetBrains).
Good resource as a jumpstart from Java to Kotlin.

Not very engaging but it will give you a grasp of some deep Kotlin concepts if you don't fall asleep first.
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Don't get me wrong, I'm a huge fan of Kotlin. But this book is too boring and hard-to-read.
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