OOPs Concept in Java

  • By
  • June 6, 2023
  • JAVA
OOPs Concept in Java

OOPs Concept in Java

We will study the fundamentals of Java’s OOPs principles in this section of the blog. The conceptual framework of object-oriented programming offers a variety of principles, including abstraction, inheritance, polymorphism, etc. These ideas seek to incorporate real-world objects into programs and develop operational procedures and characteristics for reusing them without jeopardizing protection. Java, C++, C#Python, JavaScript, Ruby, Perl, and other of the most popular and important languages for object-oriented programming are just a few examples.


OOPs in General: 

Object-Oriented Programming, sometimes known as OOPs, refers to programming languages that employ objects as the main tool for carrying out the intended action or task in the source code. The individual uses such objects to carry out the responsibilities of function given to them. Implementing real-world concepts like inheritance, concealing, variation, etc. in computing is the goal of the object-oriented programming style. The primary goal of OOP is to connect the information and the operations that use them such that only that function and no other section of the source code can access the information. 


Use of OOPs in Java code:

The foundation of Java programming is object-oriented development, which is employed to create programs via objects and classes. Information management for code execution is another way to define OOPs. In this method, programmers specify the processes that will be performed on the structure of data as well as its data format. The goal of OOps in Java is to increase code comprehension and reuse by successfully defining Java programs. Abstraction, inheritance, encapsulation, and polymorphism are the four basic foundational concepts of the object-oriented programming paradigm. These ideas seek to include actual entities in programs.


Major Concepts in the OOPs-based coding paradigm:

  1. Objects
  2. Classes
  3. Polymorphism
  4. Inheritance 
  5. Abstraction
  6. Encapsulation


Concept of Objects in the Java Code:

In Java or another language, objects that are formed from classes are always referred to as examples of that class. Such objects exhibit states and actions which are confounded in the code. These things always represent actual beings or things that can be discovered in the real world. They are also known as world run-time elements. These are all-inclusive and comprise the techniques and attributes that make data usable. Both tangible and mathematical information can be considered objects. It occupies some memory capacity and includes addresses. A dog, a chair, a tree, etc. are a few instances of such objects. When we perceive creatures as objects, they have states like color, breed, and name, as well as actions like feeding and waving their tails.


Object code Example:

Let’s say we have a class called My_Dog, and we use the term new to indicate the class name, which is followed by the object name.

public class My_Dog {

int x=10;

public static void main (String args []) {

Mydog Myobj= new My_Dog ();





Thus, a new object called My_Dog is created in the example above, and it returns the value of x, which can be the number of dogs.

For Free, Demo classes Call: 020-71173125
Registration Link: Click Here!


What are Classes in Java OOPs?

For the development of objects, classes resemble object constructors. The group of objects is referred to as a class. It is claimed that classes are reasonable quantities. Classes don’t take up any kind of storage space. A class is also referred to as an object’s container. Members of classes may include fields, techniques, or constructors. Both dynamic and example, initializers are present in a class.


An example of a class declaration is:

Modifiers: These may have default access or public access.

Class Name: First letter in the code.

Superclass: Only one parent may be extended (subclassed) by a class.

Interfaces: A class is capable of implementing many interfaces.

Body: Braces are everywhere around the body.


To construct a class, use the class keyword. Below we give a simple technique to prepare classes in Java code-


class classname {

type instance variable 1;

type instance variable 2;




type instance variable n;

type methodname 1 (parameter list) {

// body od method 


type methodname 2 (parameter list) {

// body od method 


type methodname (parameter list) {

// body od method 




Instance variables are the parameters or data declared inside a class. The methods are always composed of code. All of the techniques have the same format as the main (); neither static nor public are given for these methods.


Data Abstraction Technique:

Abstraction is a method that only shows the data that is necessary and conceals irrelevant information. It can thus be said that data concealing or scrambling is the primary goal of the abstraction process in Java OOPs. Abstraction reduces coding employees and complications by choosing data from a wide pool of data to display the information required. Additionally, method abstraction and subclasses also exist in OOPs development. A class that defines a number of method abstracts is known as an abstract class. 


A technique that has an approach specification but does not have an implementation is said to be abstract. The same pieces of data can also be used in multiple applications—abstract classes, generalized sorts of behaviors, and in the object-oriented programming hierarchy—once we have structured our object employing data abstraction. When more than one subclass does the identical operation differently and uses various implementations, abstract methods are utilized. Both normal methods and methods that are abstract can be found in an abstract class.


Inheritance feature of object-oriented programming:

One way for an object to obtain or acquire a different object’s properties is through inheritance, which additionally permits classification according to hierarchy. The concept underlying this is that we may build new classes on top of older classes; in other words, when you descend from an older class, you can utilize its fields and methods again. The connection between parent and child class is represented by inheritance. Learn about the free inheritance in Java classes at SevenMentor Institute for more information on this concept.


For instance, a whale’s species falls within the category of marine animals, which itself falls within the category of mammals. Normally a top-down classification system in this field is often known as hierarchical classification. Mammals are a more specialized type of creature, and as such, they possess additional specialized characteristics, such as teeth, cold-blooded or warm-blooded, etc. This belongs to the animal subclass, whereas creatures belong to the animal subclass. A class that inherits superclass characteristics is said to be a subclass. This is referred to as a derived class. A base subclass or parent class which is where a subclass receives its properties is known as a superclass.


Inheritance Levels: 

Single level Inheritance:

The class that is derived receives properties from the original parent class as part of inherited features. This allows for code reuse while also adding new functionality to the code. Class b, for example, inherits characteristics from class a. The fundamental or parental class is class A, and the class that is derived is class B.


Multilevel Inheritance:

This particular class originated from an additional class, which is likewise derived from the second parent class, implying that this class has an additional parental class; hence it is called multilevel inheritance.


Hierarchical Inheritance:

In this case, one parent class has a minimum of two derived classes, or three or more child subclasses have one parent class.


Multilayered or Hybrid Inheritance:

This is a combination of several multilayer inheritances. Multiple inheritances are not permitted in Java since they cause inconsistency, and this kind of inheritance is possible only through interfaces. Suppose that class A is the paternal or base class of classes b and c, and that classes b and c are, by turn, the parental or base classes of class d. Class b and group c are descended from class a, and class d is descended from class b and class c.


OOPs Polymorphism:

Polymorphism can take various shapes, or it can refer to a technique that executes a particular operation in multiple ways. It happens when several classes are connected to each other through inheritance. The polymorphism concept in Java OOPs is classified into two main categories: called compile-time polymorphism and runtime polymorphism. Overloading a method that is static in Java is a prime instance of compile-time polymorphism. A dynamic function delivery, also known as run time polymorphism, is an approach whereby a call to an overriding technique is processed at run time instead of during compilation. The modified function is constantly invoked via the referenced variables in this method. Polymorphism can be achieved by employing the overloading of methods and method overloading. Polymorphism is frequently expressed as a single interface with many methods. This simplifies things by enabling the same layout to be used for multiple types of actions. 


Primary segments of polymorphism in Java:

  • Polymorphism in Static / Compile-Time
  • Dynamic Polymorphism / Runtime Polymorphism


The major difference between compile-time and run-time polymorphism is as follows-

Compile-Time Polymorphism in Java is referred to as Static Polymorphism. This function is to be used to resolve at compile-time using the method overloading technique. Similarly, runtime polymorphism, also known as Dynamic Binding, is used to invoke an overridden method that is determined automatically at runtime instead of at compilation time. 


What exactly is encapsulation in OOPs?

Encapsulation is a notion in OOPs; it is a technique that binds combined code and information into a single unit, keeping both protected from outside intervention and misuse. During this procedure, the data is concealed from different classes and can only be accessed via the techniques of the present class. As a result, it is additionally referred to as data concealing. Encapsulation functions as a protective covering that prohibits intruders from accessing the software and data. These are managed using a clear interface. Encapsulation is performed by designating variables private and giving public settings and achieving ways of changing and viewing the values of variables. Encapsulation makes a class’s properties read-only or write-only. This technique is also more reusable. Encapsulated software is also simple to unit test.

For Free, Demo classes Call: 020-71173125
Registration Link: Click Here!


The Benefits of the OOPs Technique in Software Development: 

Below are some of the major benefits of OOPs in Java-based development:


Reusability of code:

While we mention re-usability, we imply “write once, use multiple times,” which entails using certain features instead of developing them over and over again, which can be accomplished by using classes. We can use it as many times as we need to.


Redundancy of information:

It constitutes a single of the most significant benefits of OOPs. When the identical piece of information is held in two different locations, this circumstance occurs at the data repository. If we wish to use comparable features in several classes, we can simply define standard class descriptions by inheriting them.


Safety of the code:

Data concealing and encapsulation are employed to filter out restricted exposure, ensuring that we provide only the data that is required to view while maintaining security.


Upkeep of the code:

It is simple to adapt or maintain current code to create fresh objects with minor modifications from the ones that already exist. This saves programmers from having to redo work and alter current codes by adding new updates.


Advantages of Design:

Designers will go through a longer and more comprehensive design phase, resulting in superior designs. When the program reaches its critical point, it will be straightforward to code all non-oops independently.


Is it possible for polymorphism, encapsulation, and inheritance to coexist in a Java code?

When we incorporate inheritance, polymorphism, and encapsulation in the same code to create a programming environment, we get far more durable and adaptable software that follows the program-oriented approach. A well-designed conceptual framework for the class hierarchy is the foundation for recycling the code that we invested many hours in developing and testing. Encapsulation makes it possible to change our class implementations as time passes without affecting the source code that relies on the public representations of our classes. Polymorph ism enables us to write legible, and tidy codes with sensible flow. Thus implementing all of them is actually possible and may not cause any coding errors. However proper logic-based implementation of such a mixture is required to achieve the best results.


End words:

If you wish to become a professional OOPs-based software programmer or enhance your Java programming skills, SevenMentor Institute’s Object Oriented Programming in Java is for you. People enroll in this course for a variety of reasons, and we are very thrilled to engage with everyone. You will learn how to put cool individual endeavors that you’ve been deliberating about into action. So join us at the Java Development Course in Pune as early as possible.

For Free, Demo classes Call: 020-71173125
Registration Link: Click Here!

Submit Comment

Your email address will not be published. Required fields are marked *