Book Image

Java 9 Programming By Example

By : Peter Verhas
Book Image

Java 9 Programming By Example

By: Peter Verhas

Overview of this book

This book gets you started with essential software development easily and quickly, guiding you through Java’s different facets. By adopting this approach, you can bridge the gap between learning and doing immediately. You will learn the new features of Java 9 quickly and experience a simple and powerful approach to software development. You will be able to use the Java runtime tools, understand the Java environment, and create Java programs. We then cover more simple examples to build your foundation before diving to some complex data structure problems that will solidify your Java 9 skills. With a special focus on modularity and HTTP 2.0, this book will guide you to get employed as a top notch Java developer. By the end of the book, you will have a firm foundation to continue your journey towards becoming a professional Java developer.
Table of Contents (17 chapters)
Title Page
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Generics


The generics feature was introduced into Java in version 5. To start with an example, our Sortable interface until now was this:

package packt.java9.by.example.ch03; 
public interface SortableCollection { 
    Object get(int i); 
    int size(); 
}

After introducing generics, it will be as follows:

package packt.java9.by.example.ch03; 

public interface SortableCollection<E> { 
    E get(int i); 
    int size(); 
}

The E identifier denotes a type. It can be any type. It says that a class is a sortable collection if it implements the interface, namely the two methods— size and get. The get method should return something that is of type E, whatever E is. This may not make too much sense up until now, but you will soon get the point. After all, generics is a difficult topic.

The Sort interface will become the following:

package packt.java9.by.example.ch03; 
import java.util.Comparator; 
public interface Sort<E> { 
    void sort(SortableCollection<E> collection); 
    void...