Book Image

Modular Programming in Java 9

By : Koushik Srinivas Kothagal
Book Image

Modular Programming in Java 9

By: Koushik Srinivas Kothagal

Overview of this book

The Java 9 module system is an important addition to the language that affects the way we design, write, and organize code and libraries in Java. It provides a new way to achieve maintainable code by the encapsulation of Java types, as well as a way to write better libraries that have clear interfaces. Effectively using the module system requires an understanding of how modules work and what the best practices of creating modules are. This book will give you step-by-step instructions to create new modules as well as migrate code from earlier versions of Java to the Java 9 module system. You'll be working on a fully modular sample application and add features to it as you learn about Java modules. You'll learn how to create module definitions, setup inter-module dependencies, and use the built-in modules from the modular JDK. You will also learn about module resolution and how to use jlink to generate custom runtime images. We will end our journey by taking a look at the road ahead. You will learn some powerful best practices that will help you as you start building modular applications. You will also learn how to upgrade an existing Java 8 codebase to Java 9, handle issues with libraries, and how to test Java 9 applications.
Table of Contents (19 chapters)
Title Page
Credits
About the Author
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface

Setting up the JDK


In order to write Java 9 code, you'll first need to download and install the Java 9 SDK (referred to as the Java Development Kit or JDK). In this book, we'll be using the OpenJDK build available at http://jdk.java.net/9/. When you navigate to the URL, you'll see a list of available downloads based on the platform you are using, as shown here:

Make sure you choose the download for your platform in the JDK column, not the JRE column. After accepting the license agreement, you should be able to download an installer for your platform. Run the installer and choose the defaults; after this, you should have JDK 9 installed in your machine:

After the installation is complete, it's a good idea to verify that the JDK installation and configuration process completed successfully. You do that by opening a Command Prompt or terminal window. Type the command java -version to output the version of the java command currently in the PATH:

Note

Note that the installer adds the location of...