What is an Object in OOPs(Object Oriented Programming)

What are the main principles of OOP?

There are four main principles of OOP. Now, let's discuss all these 4 in a little more detail:

1. Encapsulation: It is the mechanism of hiding the internal state of an object and requiring all interaction to be performed through the object's methods. It helps protect the integrity of the data and reduces system complexity.
2. Abstraction: It simplifies complex reality by modeling classes appropriate to the problem, and working at the most relevant level of inheritance for a particular aspect of the problem.
3. Inheritance: It allows a class to inherit characteristics (methods and properties) from another class. This supports reusability and can simplify maintenance by allowing changes to be made in one place.
4. Polymorphism: Polymorphism lets routines use variables of different types at different times, enabling a single interface to control access to a general class of actions.

What is the Object in OOPs?

In the context of Object-Oriented Programming, an object is an instance of a class that encapsulates data and functionality including that data. Objects serve as the basic building blocks of OOP applications, embodying both the properties (data) and behaviors (methods) relevant to the software being developed. Objects are created using classes, which define their structure; once instantiated, objects operate independently but can interact through defined interfaces, following the principles of encapsulation and abstraction. This setup not only facilitates more modular and scalable application development but also enhances the reusability and maintainability of code.
 

Characteristics of Object

We have covered what is an object in OOPs. Now, let’s discuss some characteristics of objects in OOPs.

1. State: The current values of each attribute continue to make up an object's state.
   It can be of two types: Static and Dynamic.
2. Behaviour: Behaviour describes how an object behaves and responds regarding state transitions.
3. Identity: An object's identity is a quality that makes it distinct from all other objects.
4. Responsibility: It is the function of an object that it performs within the system.

Let’s consider an example of a Student object.

• State: Name, Age, Gender, Address.
• Behavior: Reading, Writing, Running.
• Identity: ID, Registration Number.
• Responsibility: To study and get good marks.

Object-based languages

Object-based programming languages are programming languages that support object-oriented programming concepts to some extent but differ from fully object-oriented languages in that they lack certain features, such as inheritance. 

In object-based languages, objects are created from classes, just like in object-oriented languages. Objects have properties represented by variables and methods, which are functions that can be called on the object. However, object-based languages do not support the concept of inheritance, a key feature of object-oriented languages. 

Object-based languages are often used for creating simple programs or scripting tasks, where the full power of an object-oriented language is not necessary. Examples of object-based languages include JavaScript and Visual Basic.

While object-based languages may lack some of the features of fully object-oriented languages, they can still be powerful and useful tools for certain programming tasks.

Benefits of Using Objects in Programming

Listed below are some of the benefits of using objects in programming.

1. Encapsulation

One of the key benefits of using objects is encapsulation. Encapsulation refers to the practice of hiding the implementation details of an object from the outside world. This means that the internal workings of an object are hidden from other parts of the program, which can help to reduce complexity and make the code easier to understand. Encapsulation also allows for better control over the object's behavior, as its internal state can only be modified through its methods.

2. Reusability

Another benefit of using objects is reusability. Objects can be created once and then reused in multiple parts of the program. This can help to reduce code duplication and make the program more efficient. Additionally, objects can be inherited from other objects, which can further increase reusability and reduce development time.

3. Modularity

Objects can also help to improve the modularity of a program. Modularity refers to breaking a program down into smaller, more manageable parts. Objects can represent these smaller parts, each representing a specific aspect of the program's functionality. This can make it easier to develop and maintain the program, as changes to one object will not affect other objects in the program.

4. Polymorphism

Polymorphism is another benefit of using objects. Polymorphism refers to the ability of objects to take on different forms. This means that objects can be used in various contexts without modifying the object itself. For example, a "vehicle" object could represent a car, a truck, or a motorcycle, depending on the context in which it is used.

5. Code organization

Finally, objects can help to improve the organization of code. By grouping related data and behavior into objects, the code becomes easier to understand and maintain. Objects can also be organized into hierarchies, each inheriting from a parent object. This can help to organize the code further and make it easier to navigate.

Examples of Objects

After understanding What is an object in OOPs, It’s time to see some examples of objects.

Creating Objects

class Laptop
{
    char name[20];
    int model_number;

public:
    void getdetails();
    void display();
};

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Creating a laptop object using the above-mentioned laptop class.

class Computer {
   public static void main(String []args) {
      Laptop laptop1 = new Laptop(); // object1
      Laptop laptop2 = new Laptop();  // object2


   }
}

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Creating Objects Just After Class

When a class is defined, objects can be constructed by placing their names just after the closing brace. For example,

class Laptop
{
    char name[20];
    int model_number;


public:
    void getdetails();
    void display();
} laptop1, laptop2;

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Implementation in Java

You have understood what is an object in OOPs. Now, it’s time to understand the implementation of Objects and Classes using Java.

//Laptop Class
class Laptop {
    //Declaring private instance variable or fields
    private String name;
    private int id;
    private double model;


    //Defining Parameterized Constructor
    public Laptop(String name, int id, double model) {

        this.name = name;
        this.id = id;
        this.model = model;
    }

    //Defining Non-Parameterized Constructor
    public Laptop() {

    }

    //getter and setter methods
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public double getmodel() {
        return model;
    }
    public void setmodel(double model) {
        this.model = model;
    }

    //Generating the toString() method
    @Override
    public String toString() {
        return "Laptop [name=" + name + ", id=" + id + ", model=" + model + "]";
    }

    //Adding user-defined method-> display_model()
    public void display_model() {
        System.out.println(name + " The Current Model is :: " + model);
    }


}


public class Main {


    public static void main(String[] args) {
        //Instantiate Objects Of class Laptop
        Laptop ABC = new Laptop("ABC", 2211, 10);
        Laptop XYZ = new Laptop("XYZ", 1001, 9);

        // Access the Attributes And the Methods Of Class Laptop

        // For Laptop ABC ::
        System.out.println(ABC.toString()); //Accessing the toString Method
        ABC.display_model();
        ABC.setmodel(11);


        System.out.println("The updated model of the laptop ABC:: " + ABC.getmodel());
        System.out.println("----------------------------------------------------------");

        //For Laptop XYZ ::
        System.out.println(XYZ.toString()); //Accessing the toString Method
        XYZ.display_model();
        ABC.setmodel(9);

        System.out.println("The updated model of the laptop XYZ:: " + XYZ.getmodel());
        System.out.println("----------------------------------------------------------");


    }


}

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Output

Difference Between Object and Class

• An object is a data field with unique states and behaviour.
• A class serves as a blueprint for creating objects.

In this section, we will discuss the difference between Object and class.

You can also read about the Multiple Inheritance in Java.

Criticism of OOP

Despite its widespread adoption and numerous benefits, Object-Oriented Programming (OOP) has faced various criticisms over the years, particularly from proponents of other programming paradigms. Some of the primary criticisms are:

1. Complexity: Critics argue that OOP can introduce unnecessary complexity into software design, with excessive layering and interaction between objects making systems hard to understand and maintain.
2. Performance Issues: Object-oriented systems might suffer from performance overhead due to the additional layers of abstraction and encapsulation. This can lead to slower execution times compared to procedural programming, especially in systems where performance is critical.
3. Overhead of Objects: The instantiation of objects, especially in large numbers, can lead to significant memory and processing overhead, which may not be justifiable for simple tasks.
4. Inappropriate Use: OOP is not always the optimal approach for every programming problem. Its use in scenarios that do not naturally fit the object-oriented model can lead to awkward and convoluted code architectures.
5. Steep Learning Curve: The principles of OOP, such as inheritance and polymorphism, can be challenging for new developers to grasp, potentially leading to incorrect implementation and issues in code maintainability.
6. Encapsulation and Accessibility: While encapsulation is touted as a benefit, it can also be a hindrance when it limits access to necessary methods and properties within an object, forcing developers to either break encapsulation or use inefficient workarounds.
    

Frequently Asked Questions

What is the main purpose of using OOPs concepts?

OOP concepts assist the programmer in managing and accessing data and enhance the readability and reuse of code. The four pillars of OOPs or four basic principles of OOPs are abstraction, encapsulation, inheritance, and polymorphism.

Why do we need objects in OOPs?

Objects are a fundamental concept in object-oriented programming and allow for encapsulation, reusability, modularity, polymorphism, and code organization. By using objects, developers can create more efficient, maintainable, and scalable code that is easier to understand and adapt to changing requirements.

Is it always necessary to create objects from class?

No, it is not always necessary to create objects from a class. However, in object-oriented programming, objects are typically created from classes, as classes define the properties and behaviours of the objects, and only creating an object makes it possible to access the attributes and functions of the class.

What is used to create an object?

In object-oriented programming, objects are created from classes. To create an object, first, a class is defined with the desired properties and behaviours. Then, an instance of the class is created using the "new" keyword, which allocates memory for the object and initializes its properties. The resulting object can then perform various tasks within the program.

Conclusion

In this article, we discussed the fundamentals of Object-Oriented Programming (OOP), like its main principles, and the role of objects within this. We explained the difference between objects and classes, highlighting that objects require memory allocation upon creation, unlike classes. Moreover, we also discussed the advantages and criticisms of OOP.

• Features of Object Oriented Programming
• Characteristics of Object Oriented Programming
• Classes and Objects.
• Four Pillars of OOPs.

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