Java in a Nutshell, 9th Edition

Chapter 1. Introduction to the Java Environment

Welcome to Java in 2026.

You may be coming to the Java world from another tradition, or maybe this is your first taste of computer programming. Whatever road you may have traveled to get here, welcome—​we’re glad you’ve arrived.

Java is a powerful, general-purpose programming environment. It is one of the most widely used programming environments in the world and has been exceptionally successful in business and enterprise computing for over 30 years.

In this chapter, we’ll set the scene by describing the Java language (which programmers write their applications in), the Java execution environment (known as the “Java Virtual Machine,” which actually runs those applications), and the Java ecosystem (which provides a lot of the value of the programming environment to development teams).

All three of these concepts (language, execution environment, and ecosystem) are habitually referred to just as “Java,” with the precise usage inferred from context. In practice, they are such connected ideas that this isn’t as confusing as it might first seem.

We’ll briefly cover the lifecycle of a Java program, then clear up some common questions about Java, and then move on to discuss the differences between Java and other environments. As Java has been around for many years, some criticisms have been made. We’ll address those criticisms and then briefly talk about the history of the Java language and virtual machine and explain how that relates ...