Vergil Silva - Java Programming for Beginners: Improve your Software Engineering Skills by Learning to Code using an Object-Oriented Program. Learn about the Virtual Machine, Javascript, and Machine Code (2022)

Java Programming for Beginners

Improve your Software Engineering Skills by Learning to Code using an Object-Oriented Program. Learn about the Virtual Machine, Javascript, and Machine Code (2022)

Vergil Silva

Copyright 2022

All rights reserved.

ISBN:

CONTENTS

INTRODUCTION

Java is a programming language that is widely used on the Internet and in computer applications. It is a free download option that enables users to get the most recent versions and apply updates. This programming language can be found in the vast majority of today's web apps and computing technology. Java's scalability makes it suited for use in a broad variety of applications, including apps for small electronic devices such as cell phones and software solutions for large-scale operations such as data centers. Java's growing popularity can be attributed to its robust functional capabilities and solid security credentials.

Java is a programming language developed by Sun Microsystems, which was later acquired by Oracle Corporation. It is intended to run on any Java-enabled operating system. This is what made the language so popular: the developer only had to write the program once, and it could then operate on any operating system without the programmer having to change the code.

The Java programming language is used to create the majority of current apps around the world. The Java programming language is used to build the majority of the server-side and business logic components of major apps.

Throughout the course of this book, you will learn how to construct programs like the one above, as well as advanced concepts that will allow you to begin writing full application programs.

Some of Java's design goals are listed below:

• The language is designed to be written only once and run on any operating system.
• The language should support a wide range of software engineering principles. The portability of a product is critical. This is why Java can operate on the Windows, Linux, and MacOS operating systems.

Internationalization requires a lot of support.

Java is designed to be used for developing programs for both hosted and embedded systems.

Other design goals are discussed next:

Strong Type Checking

Java is a strong type language. Every variable that is defined needs to be attached to a data type.

You dont need to understand the complete program for now, but lets just have a quick look at 2 lines of the code.

1) int i=5;

Here we are defining something known as a variable, which is used to hold a value. The value that can be stored depends on the data type. In this example, we are saying that i is of the type int or Integer, which is a numeric data value.

Array Bounds Checking

At runtime, Java will check whether the array has the required number of values defined. If one tries to access a value which is outside the bounds of the array, an exception will be thrown.

You dont need to understand the complete program for now, but lets just have a quick look at the following lines of the code.

1) int[] array1 = new int[2];

Here we are declaring an array, which is a set of integer values. The value of 2 means that we can only store two values in the array.

2) array1[0] = 1; array1[1] = 2; array1[2] = 3;

With this code, we can see that we are assigning 3 values to the array. When you run this program, you will get an error because the program will see that the array has gone out of its maximum allowable bounds of two. You will get the below error at runtime. Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 2 at HelloWorld.main(HelloWorld.java:8)

Why Java is important?

Next, Java has syntax and features that resemble other programming languages like C and C++. If you have any prior programming experience, you will find learning Java a breeze. Even if you are totally new to programming, you can rest assured that Java is designed to be a relatively easy language to learn. Most programmers find it easier to learn Java than say, C or C++.

Java is also designed to be platform-independent. As mentioned earlier, Java code is compiled into bytecode first, which can be run on any machine that has the Java Virtual Machine.

Hence with Java, you can write the code once and run it anywhere you want.

Why Java?

Of course, one of the key reasons to use Java is its focus on Object oriented programming.

Object-oriented programming, or OOP is a type of programming language model which allows the programs code to be organized around data, rather than functions and logic, which is known as procedural programming.

These data clusters are organized into things called objects, hence the moniker of object-oriented programming.

These objects are created by something called classes, understood here in the traditional sense of how classes are: types of objects, allowing the programmer to classify them according to two major criteria: attributes and methods.

The attributes of a class are the raw data that will create the object: these are its descriptors, such as the values that it possesses, and other relevant data that will make up the object. The second criterion is the method of the object.

This method is the behavior, or the logical sequences contained within the class, describing how it interacts or can be interacted with natively.

Chapter 1

Java Basics

One of the primary reasons to adopt Java is its emphasis on object-oriented programming. Object-oriented programming, also known as "OOP," is a programming language model that allows program code to be arranged around data rather than functions and logic, as in procedural programming.

These objects are formed by "classes," which are interpreted in the classic sense of how classes are sorts of objects that allow the programmer to "classify" them based on two key criteria: attributes and methods.

The attributes of a class are the raw data that will be used to generate the object: these are its descriptors, such as the values it holds, and other pertinent data that will be used to create the object.

The object's "method" is the second requirement.

To illustrate, suppose there is a class called "Human." This "class" will include characteristics like height, weight, gender, and race. Methods in the "human" class can also include "run," "walk," and "speak." These theoretical components comprise the "human" class, which serves as a blueprint for an object.

Now that the class has been defined, the programmer can use the "human" class as a blueprint to generate an object.

They can use the class "Human" to "fill" its attributes, such as height, weight, gender, and race. Furthermore, the object already has built-in functions such as "run," "walk," and "talk," so when an object named "Mike" from the "Human" class is created, it already contains the functions to run, walk, and talk, without the need for the programmer to code those specific functions again, as they are already "inherent" in the created object.