Getting ready for our journey toward OOP with Java 9

In this book, you will learn to take advantage of all the object-oriented features included in the Java programming language version 9, known as Java 9. Some of the examples might be compatible with previous Java versions, such as Java 8, Java 7, and Java 6, but it is essential to use Java 9 or later because this version is not backwards compatible. We won't write code that is backwards compatible with previous Java versions because our main goal is to work with Java 9 or later and to use its syntax and all of its new features.

Most of the time, we won't use any IDE (Integrated Development Environment), and we will take advantage of JShell and many other utilities included in the JDK. However, you can use any IDE that provides a Java 9 REPL to work with all the examples. You will understand the benefits of working with a REPL in the next sections. You will definitely benefit from an IDE in the last chapter where you will explore the new modularity features introduced with Java 9.

Tip

You don't need any previous experience with the Java programming language to work with the examples in the book and learn how to model and create object-oriented code with Java 9. If you have some experience with C#, C++, Python, Swift, Objective-C, Ruby, or JavaScript, you will be able to easily learn Java's syntax and understand the examples. Many modern programming languages have been borrowing features from Java and vice versa. Therefore, any knowledge of these languages will be extremely useful.

In this chapter, we will install the required software on Windows, macOS, or Linux. We will understand the benefits of working with a REPL, specifically, JShell, to learn object-oriented programming. We will learn how to run Java 9 code in the JShell and how to load the source code samples in the REPL. Finally, we will learn how to run Java code on Windows, macOS, and Linux from the command line or terminal.