Book Image

Introduction to JVM Languages

Book Image

Introduction to JVM Languages

Overview of this book

Anyone who knows software development knows about the Java Virtual Machine. The Java Virtual Machine is responsible for interpreting Java byte code and translating it into actions. In the beginning, Java was the only programming language used for the JVM. But increasing complexity of the language and the remarkable performance of the JVM created an opening for a new generation of programming languages. If you want to build a strong foundation with the Java Virtual Machine and get started with popular modern programming languages, then this book is for you. The book will begin with a general introduction of the JVM and its features, which are common to the JVM languages, helping you get abreast with its concepts. It will then dive into explaining languages such as Java, Scala, Clojure, Kotlin, and Groovy and will show how to work with each language, their features, use cases, and pros and cons. By writing example projects in those languages and focusing on each language’s strong points, it will help you find the programming language that is most appropriate for your particular needs. By the end of the book, you will have written multiple programs that run on the Java Virtual Machine and know about the differences between the various languages.
Table of Contents (21 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Class organization with packages


All JVM languages define their own syntaxes for creating classes and instantiating objects, but in the end, they produce class files that would run on the JVM. In order to be able to run on the JVM and be able to offer interoperability with classes written in other languages on the JVM platform, they have to follow JVM's requirements for organizing classes. We'll discuss the following topics:

  • Packages
  • Choosing a package
  • Package examples
  • Fully qualified class names

Note

Knowledge of packages is required to understand the organization of the Java Class Library and how to run JVM applications on the command line. Both these topics are discussed in this chapter.

What are packages?

Most languages covered in this book support grouping classes in packages. Classes that are grouped inside a package form a unique namespace. This is the fundamental feature of a JVM. Some languages cannot group classes in a package themselves, but they still support referencing classes inside...