Book Image

Learn Java 12 Programming

By : Nick Samoylov
Book Image

Learn Java 12 Programming

By: Nick Samoylov

Overview of this book

Java is one of the preferred languages among developers, used in everything right from smartphones, and game consoles to even supercomputers, and its new features simply add to the richness of the language. This book on Java programming begins by helping you learn how to install the Java Development Kit. You will then focus on understanding object-oriented programming (OOP), with exclusive insights into concepts like abstraction, encapsulation, inheritance, and polymorphism, which will help you when programming for real-world apps. Next, you’ll cover fundamental programming structures of Java such as data structures and algorithms that will serve as the building blocks for your apps. You will also delve into core programming topics that will assist you with error handling, debugging, and testing your apps. As you progress, you’ll move on to advanced topics such as Java libraries, database management, and network programming, which will hone your skills in building professional-grade apps. Further on, you’ll understand how to create a graphic user interface using JavaFX and learn to build scalable apps by taking advantage of reactive and functional programming. By the end of this book, you’ll not only be well versed with Java 10, 11, and 12, but also gain a perspective into the future of this language and software development in general.
Table of Contents (25 chapters)
Free Chapter
1
Section 1: Overview of Java Programming
5
Section 2: Building Blocks of Java
15
Section 3: Advanced Java

Interface

In the Abstraction/Interface section, we talked about an interface in general terms. In this section, we are going to describe a Java language construct that expresses it.

An interface presents what can be expected of an object. It hides the implementation and exposes only method signatures with return values. For example, here is an interface that declares two abstract methods:

interface SomeInterface {
void method1();
String method2(int i);
}

And here is a class that implements it:

class SomeClass implements SomeInterface{
public void method1(){
//method body
}
public String method2(int i) {
//method body
return "abc";
}
}

An interface cannot be instantiated. An object of an interface type can be created only by creating an object of a class that implements this interface:

SomeInterface si = new SomeClass(); 

If not all...