Chapter 1, Getting Started with Java 9, gives you a jump start in Java, helping you install it on your computer and run your first interactive programs using the new Jshell.

Chapter 2, The First Real Java Program - Sorting Names, teaches you how to create a development project. This time, we will create program files and compile the code.

Chapter 3, Optimizing the Sort - Making Code Professional, develops the code further so that the code is reusable and not only a toy.

Chapter 4, Mastermind - Creating a Game, is when some fun starts. We develop a game application that is interesting and not as trivial as it first seems, but we will do it.

Chapter 5, Extending the Game - Run Parallel, Run Faster, shows you how to utilize the multi-processor capabilities of modern architecture. This is a very important chapter that details technologies, that only a few developers truly understand.

Chapter 6, Making Our Game Professional - Do it as a Webapp, transforms the user interface from command-line to web browser-based, delivering better user experience.

Chapter 7, Building a Commercial Web Application Using REST, takes you through the development of an application that has the characteristics of many commercial applications. We will use the standard REST protocol which has gained ground in enterprise computing.

Chapter 8, Extending Our E-Commerce Application, helps you develop the application further utilizing modern language features such as scripting and lambda expressions.

Chapter 9, Building an Accounting Application Using Reactive Programming, teaches you how to approach some problems using reactive programming.

Chapter 10, Finalizing Java Knowledge to a Professional Level, gives a bird's-eye view of developer topics that play an important role in the life of a Java developer, and which will guide you further in working as a professional developer.

To immerse into the content of this book and to soak up most of the skills and knowledge, we assume that you already have some experience with programming. We do not assume too much but hope that you already know what a variable is, that computers have memory, disk, network interfaces, and what they generally are. In addition to these basic skills, there are some technical requirements to try out the code and the examples of the book. You need a computer—something that is available today and can run Windows, Linux, or OSX. You need an operating system and, probably, that is all you need to pay for. All other tools and services that you will need are available as open source and free of charge. Some of them are also available as commercial products with an extended feature set, but for the scope of this book, starting to learn Java 9 programming, those features are not needed. Java, a development environment, build tools, and all other software components we use are open source.

This book is for anyone who wants to learn the Java programming language. You are expected to have some prior programming experience with another language, such as JavaScript or Python, but no knowledge of earlier versions of Java is assumed.

In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "The following function f has a side effect, though."

A block of code is set as follows:

package packt.java9.by.example.ch03; 

public interface Sort { 
 void sort(SortableCollection collection); 
}

If there is a line (or lines) of code that needs to be highlighted, it is set as follows:

id=123 
title=Book Java 9 by Example
description=a new book to learn Java 9 
weight=300 
width=20 
height=2 
depth=18

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "Clicking the Next button moves you to the next screen."

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To send us general feedback, simply e-mail [email protected], and mention the book's title in the subject of your message.

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