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Introduction to JVM Languages
Introduction to JVM Languages

Introduction to JVM Languages: Get familiar with the world of Java, Scala, Clojure, Kotlin, and Groovy

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Paperback Jun 2017 450 pages 1st Edition
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NZ$14.99 NZ$57.99
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NZ$71.99
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Paperback Jun 2017 450 pages 1st Edition
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Introduction to JVM Languages

Developing on the Java Virtual Machine

In this chapter, we will take an in-depth look at a Java Virtual Machine (JVM). We will focus on concepts that every JVM developer should know, regardless of the chosen programming language. This is what we will cover in this chapter:

  • Java Development Kit (JDK)
  • Class organization with packages
  • Java Class Library
  • Running JVM applications on the command line
  • Installing the Eclipse Integrated Development Environment (Eclipse IDE)

While this book covers Windows, macOS, and Linux (Ubuntu) operating systems, paths will often be shown in Windows style only. When using macOS and Linux systems, be sure to rewrite the paths using the rules of your operating system.

JDK

Developers who want to develop on a JVM should always install JDK. It bundles the Java Runtime Environment (JRE), the Java compiler, and various development tools, some of which we will explore in this chapter. Even if you are planning to do most of your JVM development in a language other than Java, it is strongly advised that you still install the complete JDK. Many prominent development tools require a fully installed JDK to run. Also, sooner or later, you'll probably want to use some of the tools that are only included in JDK.

The recent version of the Linux distribution of the Raspberry Pi installs the Java SE Embedded 8 JDK automatically when using the default Raspian installation options. Be aware though that, often, the supplied version is not up-to-date. We are not aware of other major operating systems that bundle JDK with their default installation. We will...

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
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...

Java Class Library

The Java Class Library is also simply known as the Java API. It's a huge collection of prebuilt classes that is distributed with the Java SE platform. Some of the more important themes of the library include:

  • Definitions and implementations of common data structures
  • Console I/O
  • File I/O
  • Mathematics
  • Networking
  • Regular expressions
  • XML creation and processing
  • Database access
  • GUI toolkits
  • Reflection

We cannot cover the complete Java Class Library here, but we want to give some examples of the APIs that are available and give you pointers on where to find the classes you need. Before we look at specific classes, we will take a look at the main organization. We'll cover the following topics:

  • Java Class Library organization
  • Package overview
  • Fundamental classes from the java.lang package
  • Collections API, namely java.util.ArrayList and java.util.HashMap
  • ...

Running JVM applications on the command line

Running applications on a JVM is often considered a fairly complex topic. As mentioned in the previous chapter, compilers that target a JVM compile their source code to binary files with a .class file extension. There are a few rules that must be followed before you can have a JVM instance run the code inside the .class files:

  • At least one class must have a static main() method
  • All the class files should be stored in specific directories
  • The ClassPath has to be specified
  • Class files can optionally be placed inside a JAR archive container
  • To run the program, the java command is used

We will take a quick look at each rule. Then, to demonstrate these concepts as clearly as possible, we will be doing a hands-on demonstration project in Java.

...

Eclipse IDE

As we have seen in the previous section, using a simple text editor to create JVM programs can be a quite cumbersome process. In some languages, including Java, you'll have to make sure that the package name structure matches the directory structure of the source code. As we will soon see, there are more rules that some languages impose on the developer. Java requires that the source code filename should match the corresponding class name. Also, you have to manually specify the ClassPath when running programs. The list goes on.

In the JVM world, most programmers use the sophisticated IDE to develop their projects. Both commercial and open source IDEs that support the JVM concept are available on the market. Java support is extremely strong on all popular IDEs. Java programmers can expect the following features in a modern IDE:

  • First is the autocompletion feature...

JDK


Developers who want to develop on a JVM should always install JDK. It bundles the Java Runtime Environment (JRE), the Java compiler, and various development tools, some of which we will explore in this chapter. Even if you are planning to do most of your JVM development in a language other than Java, it is strongly advised that you still install the complete JDK. Many prominent development tools require a fully installed JDK to run. Also, sooner or later, you'll probably want to use some of the tools that are only included in JDK.

The recent version of the Linux distribution of the Raspberry Pi installs the Java SE Embedded 8 JDK automatically when using the default Raspian installation options. Be aware though that, often, the supplied version is not up-to-date. We are not aware of other major operating systems that bundle JDK with their default installation. We will cover the following JDK-related topics:

  • Installing JDK (Windows, macOS, and Linux)
  • Exploring JDK
  • JRE

Installing JDK

We will...

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Key benefits

  • This guide provides in-depth coverage of the Java Virtual Machine and its features
  • Filled with practical examples, this book will help you understand the core concepts of Java, Scala, Clojure, Kotlin, and Groovy
  • Work with various programming paradigms and gain knowledge about imperative, object-oriented and functional programming

Description

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.

Who is this book for?

This book is meant for programmers who are interested in the Java Virtual Machine (JVM) and want to learn more about the most popular programming languages that can be used for JVM development. Basic practical knowledge of a modern programming language that supports object-oriented programming (JavaScript, Python, C#, VB.NET, and C++) is assumed.

What you will learn

  • Gain practical information about the Java Virtual Machine
  • Understand the popular JVM languages and the Java Class Library
  • Get to know about various programming paradigms such as imperative, object-oriented, and functional
  • Work with common JVM tools such as Eclipse IDE, Gradle, and Maven
  • Explore frameworks such as SparkJava, Vert.x, Akka and JavaFX
  • Boost your knowledge about dialects of other well-known programming languages that run on the JVM, including JavaScript, Python, and Ruby

Product Details

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Publication date : Jun 28, 2017
Length: 450 pages
Edition : 1st
Language : English
ISBN-13 : 9781787127944
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Length: 450 pages
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Language : English
ISBN-13 : 9781787127944
Category :
Languages :
Tools :

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Table of Contents

14 Chapters
Java Virtual Machine Chevron down icon Chevron up icon
Developing on the Java Virtual Machine Chevron down icon Chevron up icon
Java Chevron down icon Chevron up icon
Java Programming Chevron down icon Chevron up icon
Scala Chevron down icon Chevron up icon
Scala Programming Chevron down icon Chevron up icon
Clojure Chevron down icon Chevron up icon
Clojure Programming Chevron down icon Chevron up icon
Kotlin Chevron down icon Chevron up icon
Kotlin Programming Chevron down icon Chevron up icon
Groovy Chevron down icon Chevron up icon
Groovy Programming Chevron down icon Chevron up icon
Other JVM languages Chevron down icon Chevron up icon
Quiz Answers Chevron down icon Chevron up icon
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