What this book covers

Chapter 1, Programming Interactively within Your Project, provides a short introduction about the JVM (Java Virtual Machine) and some of the key features that have made Java successful. We will then start getting our hands dirty and experiment with the Scala REPL (short for, Read Eval Print Loop), a powerful tool to program interactively. We will introduce some of the powerful constructs of Scala that make programming not only enjoyable but also intuitive and productive.

Chapter 2, Code Integration, is about making Scala and Java code collaborate under the same code base. Topics of interest in this chapter are interoperability between Java and Scala collections, and wrapping existing Java libraries with Scala. Moreover, we will touch on the topic of coding style, in particular, by comparing the well-established Java coding best practices to the more recent Scala guidelines.

Chapter 3, Understanding the Scala Ecosystem, helps you to know the Scala development ecosystem and its surrounding tools, most of which are being more or less inherited from Java. In particular, Java frameworks such as Maven, and IDEs such as Eclipse, cannot be overlooked. In addition to the essential elements of the development cycle, we will cover Scala-specific tools such as SBT, Scala Worksheets, and the introduction of Typesafe's Activator and its templates.

Chapter 4, Testing Tools, is a follow-up on the essential tools of a Scala developer, focusing on reviewing most of the useful tools for unit, integration, and functional testing of test data as well automated property-based testing.

Chapter 5, Getting Started with the Play Framework, will give you a concrete introduction to the Play Framework, where we will show you some of the cool features of Play that make one want to migrate from a more traditional servlet/J2EE model.

Chapter 6, Database Access and the Future of ORM, covers tackling the persistence of data in relational databases, whether you want to reuse well-established technologies such as JPA/Hibernate, or move to more innovative yet promising alternatives such as SLICK (Scala Language-Integration Connection Kit), an interesting alternative to traditional ORM merely based on the power of the Scala language. Moreover, we will see how to reverse-engineer the existing relational databases into Play CRUD applications as a starting point in migrating Java projects.

Chapter 7, Working with Integration and Web Services, covers technologies that are found everywhere in today's Java development. In this chapter, we will explore how integrating with the external systems applies to the Scala world and what the benefits are. Topics included in this chapter relate to Web Services through SOAP XML, REST, and JSON.

Chapter 8, Essential Properties of Modern Applications – Asynchrony and Concurrency, refers to two aspects of scalable applications' development. To achieve better performance, software projects are often encouraged to introduce asynchronous invocations and concurrent code. Through this chapter, we will show that the more functional side of Scala can make this complexity more manageable and maintainable. We will also introduce the Akka framework, a toolkit to simplify the development of concurrent applications.

Chapter 9, Building Reactive Web Applications, takes the previous chapter one step further and introduces a new class of applications that has emerged in the market: reactive applications. They are characterized by their interactivity, the ability to push information to end users, elasticity to adapt to changes in load, and the ability to recover from failures. The aim of this chapter is to build such an app in Play using concepts learned throughout the book as well as emerging technologies such as WebSockets.

Chapter 10, Scala Goodies, concludes this book with some perspectives on the future of web development. For example, Java developers are more and more exposed to JavaScript on the client side, whether they like it or not. Another example is the emergence of Domain Specific Languages (DSLs), a nontrivial task to achieve in Java.