Book Image

Learn Scala Programming

By : Slava Schmidt
Book Image

Learn Scala Programming

By: Slava Schmidt

Overview of this book

The second version of Scala has undergone multiple changes to support features and library implementations. Scala 2.13, with its main focus on modularizing the standard library and simplifying collections, brings with it a host of updates. Learn Scala Programming addresses both technical and architectural changes to the redesigned standard library and collections, along with covering in-depth type systems and first-level support for functions. You will discover how to leverage implicits as a primary mechanism for building type classes and look at different ways to test Scala code. You will also learn about abstract building blocks used in functional programming, giving you sufficient understanding to pick and use any existing functional programming library out there. In the concluding chapters, you will explore reactive programming by covering the Akka framework and reactive streams. By the end of this book, you will have built microservices and learned to implement them with the Scala and Lagom framework.
Table of Contents (19 chapters)

To get the most out of this book

  1. We expect the reader to be comfortable with structuring and implementing simple programs in Scala and familiar with SBT and REPL. No previous knowledge of reactive programming, Akka, or microservices is required, but familiarity with the underlying concepts would be beneficial.
  2. To work with the code examples in this book, Java 1.8+ and SBT 1.2+ need to be installed. The installation of Git is recommended to simplify checking out the source code from GitHub. For those readers who don't have the prerequisite software ready, we provide installation instructions for Java and SBT in Appendix A.

Download the example code files

You can download the example code files for this book from your account at If you purchased this book elsewhere, you can visit and register to have the files emailed directly to you.

You can download the code files by following these steps:

  1. Log in or register at
  2. Select the SUPPORT tab.
  3. Click on Code Downloads & Errata.
  4. Enter the name of the book in the Search box and follow the onscreen instructions.

Once the file is downloaded, please make sure that you unzip or extract the folder using the latest version of:

  • WinRAR/7-Zip for Windows
  • Zipeg/iZip/UnRarX for Mac
  • 7-Zip/PeaZip for Linux

The code bundle for the book is also hosted on GitHub at In case there's an update to the code, it will be updated on the existing GitHub repository.

We also have other code bundles from our rich catalog of books and videos available at Check them out!

Download the color images

We also provide a PDF file that has color images of the screenshots/diagrams used in this book. You can download it here:

Conventions used

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "In Scala 2.13, StringOps has been extended with option-returning methods for string literals parsing. Supported types include all numeric types and Boolean."

A block of code is set as follows:

object UserDb {
def getById(id: Long): User = ???
def update(u: User): User = ???
def save(u: User): Boolean = ???

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

scala> val user = User("John", "Doe", "[email protected]")
user: User = User(John,Doe,[email protected])
scala> naiveToJsonString(user)
res1: String = { "name": "John", "surname": "Doe", "email": "[email protected]" }

Any command-line input or output is written as follows:

-S--c--a--l--a-- --2--.--1--3-
Lazy view constructed: -S-S-c-C-a-A-l-L-a-A- -
Lazy view forced: -S--c--a--l--a-- -List(S, C, A, L, A, )
Strict: List(S, C, A, L, A, )

Bold: Indicates a new term, an important word, or words that you see on screen.

Warnings or important notes appear like this.
Tips and tricks appear like this.