Class and Object in Java – OOPs

Class and Object in Java – OOPs

This tutorial will guide you on what is a class and how does Java deal with objects. You will know how to create a class and instantiate its object. These are the basic building blocks of object-oriented programming (OOP) in Java.

This tutorial will guide you on what is a class and how does Java deal with objects. You will know how to create a class and instantiate its object. These are the basic building blocks of object-oriented programming (OOP) in Java.

Basics Of Classes And Objects In Java

You can go through the following sections to learn about Java Class.

Contents [hide]

1 Object-Oriented Programming

2 Class in Java

3 Object in Java

4 Java Class – Example

5 Variable Types:

5.1 Class variables:

5.2 Local variables:

5.3 Instance variables:

6 Related Posts


Object-Oriented Programming

Many a time you must have come across the phrase Java is an Object-Oriented Programming Language. The term Object-Oriented denotes a concept in software development.

It is a way of organizing software in the form of objects that contain both data and the behavior of these objects. Therefore, Object-Oriented Programming Languages, generally known as OOP, provide the programming model for simplifying for software development, design and maintenance under some well-established ground rules.

The projects made in OOPS are more structured towards objects. As a result, it increases performance, maintainability, and development of the program. The main idea behind OOP is to incorporate data and behavior under the same location(objects).

The fundamental concepts supported by OOPS are:

  • Classes
  • Objects
  • Polymorphism
  • Inheritance
  • Encapsulation
  • Abstraction

Class In Java

A class in Java or any other Object-oriented Language is a blueprint for objects to follow a specific schema defined in the class.

Classes define the behavior for objects of its type. It represents a collection of properties (data and functions) for all its objects.

It supports a template for creating objects which bind code and data. Further, classes act as a means to define methods and data. It helps in maintaining access specifications for member variables using access specifiers.

Object In Java

An Object is the most fundamental entity in Java or any other Object-Oriented Language. Objects represent real-life entities because each of them could have specific behavior, identity, and data (attributes).

In Java, the object is an offspring of its class. The class has properties to reflect the object state and methods to represent the behavior.

The methods also show an object’s response to other objects. Identity is a unique name for the object assigned by the user, much like variables.

Let’s have a profound look into what are objects. If we think about this present reality, we can discover numerous articles around us, vehicles, people, and so on. Every one of these has a unique state and behavior. You can’t expect a human being to bark like a dog or a dog to speak like a human.

For example – A car, its state are – name, model no, shade, manufacturer and its behavior can be – moving, blinking the headlights, honking, etc.

If you try to compare a Java object with any real-time entity, they could probably have fundamentally same attributes.

Must Read – Java Multithreading

Java Class – Example

public class Car {

// Class Attributes - State of an object
String color;
int model_no;
String name;
String manf;

// Class Methods - Behaviour of an object
void honk() {
}

void move() {
}

void blink() {
}
}

A class can have any number of functions to access the properties of the class’s object or manipulate the properties. In the above example, move(), blink() and honk() are a few methods.

Variable Types:

A class can contain any of the accompanying variable sorts:

Class Variables:

A class variable is one which has the static keyword as a prefix in its declaration. Its definition occurs only inside a class and outside any function.

Local Variables:

These are variables which have declarations inside methods, constructors or blocks. They are local to the part of the code they belong.

Local variables come into existence when the control enters into the code block that keeps their declaration. And they vanish with the block leaving out of execution.

Instance Variables:

These variables are inside a class however outside any method. They come into existence when the class instantiates. These are accessible from any constructor or block of that specific class.

Related Posts

Constructor in Java

Inheritance in Java

Originally published on https://www.techbeamers.com


Java Fundamentals: Learn Java for absolute beginners |Simpliv

Java Fundamentals: Learn Java for absolute beginners |Simpliv

Java Fundamentals: Learn Java for absolute beginners

Description
This is the best course to learn to program in Java in Spanish from scratch and without any experience in this fabulous programming language. This is the first course where we will study the Fundamentals of Java, and we will take you step by step until you acquire the bases of the Java language and you can start to study more advanced Java topics.

The content is divided into perfectly structured levels, each level supported by the previous one, with the aim of adding Java knowledge incrementally and so you can focus on mastering the issues little by little and gradually. So ensure the success of your Java training.

We will also offer support for any doubts about the didactic material included in this Java Fundamentals course.

We manage a new teaching methodology that we have called Speed ​​Learning. This methodology consists of concise videos that go directly to the point to be studied, complemented by eBooks with explanations and step-by-step images (which you can print, or search for any text you need, or use for your offline study), since As we know we can not do text search within a video. In addition, our methodology includes perfectly structured and very didactic exercises that will allow you to accelerate your eLearning learning. No loss of time in videos where you have to watch the instructor codify an exercise, too much theory, little practice or anything like that. Our Speed ​​Learning methodology guarantees that in the shortest possible time you will acquire the necessary knowledge for the Java professional and working world.

The Java Fundamentals course includes the following topics for study:

Lesson 1 - Starting with Java Technology

The amazing world of Java programming

What is Java technology (from a practical approach)

Our first Java program from scratch

Lesson 2 - Variables and Operators in Java

Use of Variables in Java and what we use them for

Types of Data in Java and how they are classified

Management and Classification of operators in Java

Lesson 3 - Control statements in Java

Using the if-else structure and where to use it

Handling the switch structure and when applying it

Lesson 4 - Handling Loops in Java

Use of the for loop and its use

Using the while loop and how to apply it

Use of the do-while loop and when to use it

Lesson 5 - Object Oriented Programming

Introduction to Object Oriented Programming (OOP)

Handling Classes in Java

Use of Objects in Java

Lesson 6 - Functions in Java

Declaration of Methods or Functions in Java

Use and call of functions in Java

Lesson 7 - Data Management in Java

Using Arrays in Java

Management of Matrices in Java

Lesson 8 - Inheritance in Java

Inheritance Management in Java

Use of superclasses and subclasses in Java

Final Level Laboratory

Final Exercise where everything learned in this Level is integrated

At the end you get a certificate of having completed the Java Fundamentals course.

We wait for you on the other side.

Ing. Ubaldo Acosta

Founder of Global Mentoring

Passion for Java Technology

Who this course is for:

Anyone who wants to learn how to program in Java
Basic knowledge
Basic knowledge of PC use
Basic management of an operating system such as Windows, Mac or Linux
It is not necessary to know how to program, we will start from scratch !!!
The attitude and desire to start coding and learning Java once and for all from scratch!
What will you learn
Have the basics of the programming language with Java
You will know the basic syntax of the Java language
Manage the concept of Variables and Operators in Java
We will study Object Oriented Programming with Java
You will learn the Control Statements and Loops in Java
We will see the concept of Functions with Java
We will study the concept of Inheritance in Java
We will learn to use Arrays in java
We will handle the concept of Matrices in Java
We will learn to Design Classes in Java
We will make a final application with everything learned in the course
To know more:

Java Essentials : Learn Core Java From Basic to Advance

Java Essentials : Learn Core Java From Basic to Advance

Learn Java Programming Using Practical Assignments. Start Building Back-end Web Applications Robust Test Automation Frameworks By End Of The Course. Learn More!

Description
This is only Java related course and it's great because it covers just the right amount of Java which is needed to leaning programming, java.

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*************************** No Prior Coding Experience Needed ***************************

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Basic knowledge
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Java concepts are covered in the course, no experience needed
Windows/MAC computer
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You will be confident to clear test automation interviews
Understand the concepts of Object Oriented Programming Language
Complete understanding of java
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Fundamentos de Java: Aprende Java desde cero, sin misterios | Simpliv

Fundamentos de Java: Aprende Java desde cero, sin misterios | Simpliv

Fundamentos de Java: Aprende Java desde cero, sin misterios

Description
This is the best course to learn to program in Java in Spanish from scratch and without any experience in this fabulous programming language . This is the first course where we will study the Java Fundamentals, and we will take you step by step until you acquire the basics of the Java language and so you can start studying more advanced Java topics.

The content is divided into perfectly structured levels , each level supported by the previous one, with the aim of adding Java knowledge incrementally so that you can focus on mastering the issues little by little and gradually. So ensure the success of your Java training.

In other offer support of any doubt teaching materials included in this course Fundamentals of Java.

To make matters worse, we handle a new teaching methodology that we have called Speed ​​Learning. This methodology consists of concise videos that go directly to the point to study, complemented with eBooks with explanations and step-by-step images (which you can print, or search for any text you need, or use for your offline study), since as we know we cannot do text search within a video. In addition, our methodology includes perfectly structured and very didactic exercises, which will allow you to accelerate your eLearning learning. Without wasting time on videos where you have to watch the instructor codify an exercise, too much theory, little practice or anything like that. Our Speed ​​Learning methodology guarantees that in the shortest possible time you will acquire the necessary knowledge for the professional and professional world of Java.

The Java Fundamentals course includes the following topics of study:

Level. Java basics

Lesson 1 - Starting with Java Technology

The amazing world of Java programming
What is Java technology (from a practical approach)
Our first Java program from scratch
Lesson 2 - Variables and Operators in Java

Use of Variables in Java and what we use them for
Data types in Java and how they are classified
Operator Management and Classification in Java
Lesson 3 - Control sentences in Java

Use of the if-else structure and where to use it
Management of the switch structure and when to apply it
Lesson 4 - Cycle Management in Java

Use of the for cycle and its use
Use of the while cycle and how to apply it
Use of the do-while cycle and when to use it
Lesson 5 - Object Oriented Programming

Introduction to Object Oriented Programming (OOP)
Class Management in Java
Using Objects in Java
Lesson 6 - Functions in Java

Declaration of Methods or Functions in Java
Use and call of functions in Java
Lesson 7 - Data Management in Java

Using Arrangements in Java
Matrix Management in Java
Lesson 8 - Inheritance in Java

Inheritance Management in Java
Use of superclasses and subclasses in Java
Final Level Laboratory

Final Exercise where everything learned in this Level is integrated
At the end you get a certificate of having completed the Java Fundamentals course.

We wait for you from the other side.

Ing. Ubaldo Acosta

Founder of Global Mentoring

Passion for Java Technology

Who this course is for:

Anyone who wants to learn to program in Java
Basic knowledge
Basic knowledge of PC use
Basic operation of an operating system such as Windows, Mac or Linux
It is not required to know how to program, we will start from scratch !!!
The attitude and desire to start coding and learning Java once and for all from scratch !!!
What will you learn
Have the basics of the programming language with Java
You will know the basic syntax of the Java language
Will handle the concept of Variables and Operators in Java
We will study Object Oriented Programming with Java
You will learn Control Sentences and Cycles in Java
We will see the concept of Functions with Java
We will study the concept of Inheritance in Java
We will learn to use Arrangements in java
We will handle the concept of Matrices in Java
We will learn to Design Classes in Java
We will make a final application with everything learned in the course
To continue: