Miguel Angel Castiblanco Torres - Learning Concurrency in Kotlin: Build highly efficient and robust applications

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Miguel Angel Castiblanco Torres

is a software engineer living in the United States. He works as a full-stack technical leader and software designer at Globant, where he has led many successful projects for a Forbes' Top Ten World's Most Valuable Brand and Top Five Regarded Company.

Passionate about what's next, Miguel was an early adopter of Kotlin, writing about Kotlin's concurrency primitives from the first beta release of coroutines. He always keeps an eye on the new and upcoming features of Kotlin.

Peter Sommerhoff helps you to always keep learning, master new skills, and, ultimately, achieve your goals. Does that sound like something you'd like to do? If yes, ensure that you enroll for one of his courses and learn about programming languages, software design, productivity, or anything else you're interested in! He will ensure that you have a great learning experience. You can always ask him personally if you have anything at all that he can help you with. So, check out his courses, and he'll see you there!

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The era when the speed of a single core in a processor would duplicate every few years is long over. Transistors have reached unbelievably small sizes, yet heating, power consumption, and other technical and practical challenges have made it difficult to keep increasing their speed in a user-friendly, affordable way. Even more so if you consider not only desktop computers but also mobile devices such as smartphones and tablets, which are universal nowadays . So, in recent years, the focus has been put on equipping these computing devices with more than one core or more than one processor running with a balanced configuration of speed, heating, and power consumption.

The challenge becomes using those cores efficiently and effectively. An increase in the speed of a core will directly improve the execution time of the software running on it for CPU-bound operations but that is not the case when another core or processor is added. For an application to be able to take advantage of multiple cores, it needs to be written with that objective in mind. It needs to be concurrent.

However, concurrency not only benefits applications that will run in multiple cores. A concurrent application will usually work faster than a single-threaded application for IO-bound operations, even if running in a single core, because it allows the application to use the processor while other tasks are waiting for IO devices. For example, while waiting for a network operation.

So it's in your hands, as the developer, the person reading this book, to write the software that will work efficiently both in a single-core device and in a multi-core one. It's in my hands, the writer, to provide you with enough information, expressed in an understandable way, to achieve this goal. With this in mind, I have written this book, expecting nothing but basic Kotlin knowledge from you. I have tried to distill everything, from the very concepts of concurrency to the very specifics of how coroutines are compiled, for you. I have done it so that we both can do our part in bringing our users be it humans or other systems a fast yet reliable experience.

This book covers various topics in great detail, using tools such as diagrams, examples, and more often than not, real-life use cases. For that reason, most of the chapters follow the creation and modification of an RSS reader for Android, completely written in Kotlin and using only the tools and primitives provided by the language and the coroutines library. I encourage you to follow along the creation of the application and to type the code instead of copying it especially if you have only the printed version of the book so that you get to interiorize how to do it. I encourage you even more to go off-script and try some things for yourself; if you start wondering whether something can be accomplished in a certain way, it means that your brain is beginning to get a grasp of how to apply the concepts. And there's nothing better than trying something to know if it works.