Book Image

Java Projects - Second Edition

By : Peter Verhas
Book Image

Java Projects - Second Edition

By: Peter Verhas

Overview of this book

Java is one of the most commonly used software languages by programmers and developers. In this book, you’ll learn the new features of Java 11 quickly and experience a simple and powerful approach to software development. You’ll see how to use the Java runtime tools, understand the Java environment, and create a simple namesorting Java application. Further on, you'll learn about advanced technologies that Java delivers, such as web programming and parallel computing, and will develop a mastermind game. Moving on, we provide more simple examples, to build a foundation before diving into some complex data structure problems that will solidify your Java 11 skills. With a special focus on the features of new projects: Project Valhalla, Project Panama, Project Amber, and Project Loom, this book will help you get employed as a top-notch Java developer. By the end of the book, you’ll have a firm foundation to continue your journey toward becoming a professional Java developer.
Table of Contents (12 chapters)

Volatile variables

Let's modify the declaration of the o variable in our sample code as follows:

private volatile Object o = null;

The preceding code runs fine and stops after a second or so. Any Java implementation has to guarantee that multiple threads can access volatile fields and the value of the field is consistently updated. This does not mean that volatile declaration will solve all synchronization issues, but guarantees that the different variables and their value change relations are consistent. For example, let's consider that we have the following two fields incremented in a method:

private int i=0,j=0; 
  
 public void method(){ 
     i++; j++; 
 }

In the preceding code, reading i and j in a different thread may never result in i>j. Without the volatile declaration, the compiler is free to reorganize the execution of the increment operations and thus...