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)

Introduction to effects

Scala code compiles to the Java bytecode and runs on the JVM (Java Virtual Machine). As the name suggests, the JVM was not built specifically for Scala. Because of this, there is a mismatch between what is expressible with the Scala language and what the JVM supports. The consequences are twofold:

  • The compiler converts Scala features that are not supported by the JVM into the proper bytecode, mostly by creating wrapper classes. As a result, the compilation of a simple Scala program might lead to the creation of dozens or hundreds of classes, which in turn leads to decreased performance and a higher garbage footprint. These negative consequences, in essence, are just an implementation detail. As the JVM improves, it is possible to optimize the bytecode produced by the compiler for the newer versions of Java without any efforts from the application developer...