Object-Oriented Programming (OOP) Is A Programming Paradigm In Which Programs Are Organized Around The Concept Of Objects. 

Object orientation is used as one of the basic concepts of Java programming language.

Objectivism includes various concepts, but the basis of its three main ideas is as follows:

class

Class in object orientation is a pattern or template for creating objects. A class specifies what properties (variables or member properties) and behaviors (methods or member functions) an entity will have.

In other words, a class is a description or definition of a particular object type. It can be considered a map or instance of a hypothetical object with specific properties and behaviors. A class can contain variables (properties) and functions (methods) responsible for defining and managing the behavior of things related to that class.

Typically, classes have a name so that we can refer to them and create instances (objects) from them. Also, classes can define common properties and behaviors for a group of things, and then models (objects) of those classes can be created.

For example, we can define a ” Student ” class in a university management application. This class includes features such as name, student number, and field of study, and also has methods such as enrolling in courses and receiving grades. We can then create an instance (object) of this class for each new student and use its properties and behaviors.

Therefore, a class in object orientation is a specific description that determines what characteristics and behaviors an object will have, and we can create instances of things based on that class.

A class consists of various objects as follows:

• Fields: Attributes are variables defined within a class and show the state or properties of the object. They can be public, private, or protected and hold different data types, such as integers, strings, and things.
• Methods: Methods define the function and behavior of the class. They are used to perform various operations on the object. Forms can receive inputs (parameters) and return values. They can also be public, private, protected, and recursive.
• Constructors: Constructors are methods used to create an object of a class. They are responsible for setting and initializing the properties of the object. Java will create a default parameterless constructor for the course if no constructor is defined.
• Inner Classes: Inner classes are classes that are defined inside another class. They have full access to the outer class and can access its properties and methods. Inner classes can improve code organization and perform operations related to the outer class.
• Properties: Properties are property types that provide direct access to them through methods. They have getter and setter methods to receive and set property values. According to the object-oriented architecture in Java, classes have the following components:

These components, relationships, and class interactions provide more features and capabilities in Java objects and programs.

Objects

Objects in object orientation are specific examples of a class. Each object has properties (variables or member properties) and behaviors (methods or member functions) defined by the type.

For example, let’s say we have a class called “car.” This class contains properties such as brand, model, speed, and color and methods such as drive, stop, and change color. If we create an object of this class called “My Car,” that object will have the properties and behaviors defined in the “Car” class. For example, we can set the properties “Brand” to “Mercedes-Benz,” “Model” to “C-Class,” and “Color” to “Silver,” and then call the “Drive” method and put the car in let’s drive.

Therefore, objects in object orientation are active and interactive entities with specific characteristics and behaviors. They can be used in programs as main components, and by cooperating and communicating with other objects, they form the complete schedule. Each object can maintain its state, generate and respond to events, and interact with other objects to perform required tasks and functions.

Inheritance

Inheritance in object orientation is a mechanism that allows a class to inherit the properties and behaviors of a parent class to a child class. Inheritance will enable classes to share common properties and behaviors in hierarchical forms between types.

A class that defines common properties and behaviors is known as a parent class (or base class, parent class), and a class that inherits the same properties and behaviors from a parent class is known as a child class.

Using inheritance, the child class can inherit and use the properties and behaviors of the parent class. Also, the child class can define its additional properties and behaviors and add or modify the parent class.

Inheritance allows programmers to define hierarchical relationships and hierarchical structure between classes. This is very useful regarding code organization, reusability, and program extensibility. With heritage, program code and logic are organized hierarchically and represent hierarchical forms logically and organized.

For example, let’s say we have a class called “mammal” that has properties like “breath type” and “milk feeding” and also has methods like “feeding” and “breathing.” Now, we can create a child class called “Cat” that takes advantage of the “Mammal” class and defines additional properties such as “number of legs” and “reptile type.” With inheritance, the “Cat” class inherits and can use properties and behaviors shared by the “Mammal” class, plus it can add or change its properties and behaviors. In this way, we can nicely represent the hierarchical structure between classes and share common behaviors and properties by using inheritance.

In inheritance, the child class implicitly has the characteristics and behaviors of the mother class and can use them directly. If we want to change properties or modify behaviors in the child class, we can rewrite them and change them to the required form.

In short, inheritance in object orientation allows classes to be extended, share behaviors and properties, and form a hierarchical structure. This principle uses modular and reusable coding, making written programs more conceptual and organized.

Abstraction in Object Orientation in Java

In object orientation, abstraction is one of the fundamental principles used to design and implement classes and objects in the Java programming language. Abstraction means restricting access to the implementation details of a course and providing only generic functions. Using abstraction, only an object’s external behavior and functionality are known to its users, and its internal details are hidden.

In Java, abstraction is used to define classes and provide public interfaces. Relations are sets of methods that define the external functionality of an object but do not specify implementation details. By using relations, a general contract can be established between classes, and the communication between them can be determined based on this contract.

By using abstraction, open-source code becomes more usable and extensible. Classes can be designed and implemented independently by providing public relations and functions. This allows changes to the implementation without affecting existing code. Also, abstraction enables object users to interact only with public interfaces and ignore the internal details of the class, which means that changes to the class implementation do not affect users.

In short, abstraction in object orientation in Java means restricting access to the implementation details of a class and providing only generic functions. This concept allows for more usable, scalable, and extensible code design.

An example of how to use object orientation in Java

In short, object orientation in Java is based on creating classes and objects. Below is a simple example of using object orientation in Java:

Suppose we want to write a program that manages a store. One of the store manager’s duties is to manage the store’s products. Object orientation can be used to order products instead of traditional methods such as variables and separate functions.

Here, we can create a class called “Product” that holds the properties related to a product. For example, a product can have name, price, and stock quantity attributes. The “Product” class can contain variables and functions that help set and retrieve these properties.

public class Product {

    private String name;

    private double price;

    private int quantity;

    public Product(String name, double price, int quantity) {

        this.name = name;

        this.price = price;

        this.quantity = quantity;

    }

    public String getName() {

        return name;

    }

    public double getPrice() {

        return price;

    }

    public int get Quantity() {

        return quantity;

    }

    public void setQuantity(int quantity) {

        this.quantity = quantity;

    }

}

This class can create “Product” objects and use their properties and functions. For example:

public class Main {

    public static void main(String[] args) {

        Product laptop = new Product(“Laptop”, 1500.0, 10);

       

        System.out.println(“Product Name: ” + laptop.getName());

        System.out.println(“Product Price: ” + laptop.getPrice());

        System.out.println(“Product Quantity: ” + laptop.getQuantity());

       

        laptop.setQuantity(5);

        System.out.println(“Updated Quantity: ” + laptop.getQuantity());

    }

}

In this example, an object called “laptop” is created from the “Product” class, and then its properties are called through getter functions. Finally, the setter function is also used to update the product’s inventory count.

This example shows that by using object orientation, we can define the properties and functions of an object as a set of functions in a class and use them to manage and use information about that object. Also, using the “Product” class, we can create other things with similar properties and functions and improve the application.

How can we add more functions to the “Product” class?

To add more functions to the “Product” class, you can add new methods to it. New techniques can help define new properties, perform computational operations, or perform other operations on the corresponding object. You can define functions with any name and return you want.

For example, suppose you want to add a new method called “calculateTotalPrice” to the “Product” class that calculates the product’s total price based on the quantity and unit price.

public class Product {

    private String name;

    private double price;

    private int quantity;

    public Product(String name, double price, int quantity) {

        this.name = name;

        this.price = price;

        this.quantity = quantity;

    }

    // Getter and Setter methods…

    public double calculateTotalPrice() {

        return price * quantity;

    }

}

This example adds the “calculateTotalPrice” method to the “Product” class. This method calculates the total price of the product by multiplying the price and the number of units and returns the resulting value.

Now, you can use this method in your program. For example:

public class Main {

    public static void main(String[] args) {

        Product laptop = new Product(“Laptop”, 1500.0, 10);

        double totalPrice = laptop.calculateTotalPrice();

        System.out.println(“Total Price: ” + totalPrice);

    }

}

In this example, we call the “calculateTotalPrice” method on the “laptop” object to be the result in the “totalPrice” variable and finally print its value.

This way, you can add other functions to the “Product” class based on your needs. Adding new parts can add more functionality to the “Product” class and make it more functional for your applications.

An example of the concept of inheritance in Java

The concept of inheritance in Java allows you to define a new class based on an existing style, inherit the properties and behaviors of that class, and use them in your new class. This reduces code duplication and creates a hierarchical structure of categories.

For example, suppose you have a base class called “Vehicle” with properties common to all vehicles, such as name, speed, and power. Then, you want to define a car class called “Car” that has the properties and behaviors specific to cars.

In this case, you can use inheritance to define the “Car” class based on the “Vehicle” class, inheriting the common properties and behaviors and adding vehicle-specific properties and behaviors.

public class Vehicle {

    private String name;

    private int speed;

    private int power;

    public Vehicle(String name, int speed, int power) {

        this.name = name;

        this.speed = speed;

        this.power = power;

    }

    // Getter and Setter methods…

}

public class Car extends Vehicle {

    private int numOfDoors;

    public Car(String name, int speed, int power, int numOfDoors) {

        super(name, speed, power);

        this.numOfDoors = numOfDoors;

    }

    // Additional methods specific to Car class…

}

In this example, the “Vehicle” class has properties common to all vehicles. The “Car” class then inherits from the “Vehicle” class using the “extends” keyword. This causes the “Car” class to inherit the properties and behaviors of the “Vehicle” class. Also, the “Car” class has an additional property called “numOfDoors” that represents the number of doors in the car. Now, you can use these classes in your program. For example:

public class Main {

    public static void main(String[] args) {

        Vehicle vehicle = new Vehicle(“Generic Vehicle”, 100, 200);

        System. out.println(“Vehicle Name: ” + vehicle.getName());

        System. out.println(“Vehicle Speed: ” + vehicle.get speed());

        System. out.println(“Vehicle Power: ” + vehicle.get power());

        Car car = new Car(“Sedan”, 150, 250, 4);

        System. out.println(“Car Name: ” + car.getName());

        System. out.println(“Car Speed: ” + car.getSpeed());

        System. out.println(“Car Power: ” + car.get power());

        System. out.println(“Number of Doors: ” + car.getNumOfDoors());

    }

}

In this example, first, an object of the “Vehicle” class with the name “vehicle” is created, and the values ​​of its properties are displayed. Then, a thing of the “Car” class named “car” is completed, and the properties and methods of the “Vehicle” class and the “Car” class are exposed.

Consequently, the “Car” class in this example inherits from the “Vehicle” class and inherits the properties and methods of the “Vehicle” class. This shows an example of inheritance in Java, which allows you to define new types based on existing types, inherit their properties and behaviors, and use them in your new classes.

last word

Using object orientation in Java, you can design more complex programs more modularly and extensibly. Each object has responsibilities and behaviors and forms a complete program by communicating and cooperating with other things. This concept allows you to manage programs in chunks and reuse code, making code easier to understand and develop and find and fix bugs.