Introduction to the OOPs concepts in Java

Java Certification

As we all know, Java is a powerful programming language used in most mobile and Android app development, enterprise, desktop, and many applications. The main soul of Java is the OPPs concept. If you are interested in app development, learn Java online, as many tutorials and training are available on the internet. This allows developers to solve real-world problems using objects in programming. Objects are nothing but real-world entities which have state and behavior. Before getting into the OPPs concept, you need to have a clear understanding of classes and objects. Here we have discussed a brief introduction to the OOPs concept in Java.

Objects and Classes:

As mentioned above, objects are referred to as real-world entities that have states and behavior. Here state defines the properties of an object, like color and shape, which describe the appearance of an object called attributes. Behavior refers to the methods and functions associated with that object which means the actions we perform using the object. The name of an object will be declared as identity. 

Class is a user-defined blueprint or a custom template of a collection of objects. A class contains multiple objects with the same attributes and methods, so you cannot repeat the same code for different objects. 

OOPs, concept:

OOPs stands for object-oriented programming, is a methodology that allows developers to program using classes and objects. It simplifies programming by grouping similar methods and concepts into a module. There are four major concepts are defined in OOPs, they are

  1. Abstraction 
  2. Encapsulation 
  3. Polymorphism 
  4. Inheritance 


Abstraction in OOPs is defined as hiding the internal functionalities and displaying the essential details to the user. The unnecessary or complex details should be shown to the user. For example, you are making a call to somebody. All you have to do is dial the number and call them. But internally, there will be a huge mechanism. So it will only show whether the user picked up the call, declined it, or an another call. 


Encapsulation is defined as wrapping up the data and methods into a single unit. It works similarly to data hiding. The data in a class was hidden from other classes by declaring all the class variables as private and using the public methods inside the class. This means the variables can be accessed only by the function of the class. The sample syntax is given below:

public class Employee {

           private int empid;

           private String name;


The employee class was declared public and can be seen by all the users, but the private variables empid and name can only be accessed by the class itself.


Polymorphism means the ability to solve problems with various approaches. Java uses method overloading and method overriding to achieve polymorphism. Polymorphism allows a single method can be used to do different functionalities. For example, finding the area of a triangle and rectangle has been same method’s name as an area but it has different attributes and formulas. Polymorphism simplifies the code and enhances the code reusability. 


Inheritance is a powerful feature of the OOPs concept, allowing us to inherit a class’s attributes and methods. In simple, we can derive one class from another class. The default class will be known as the parent class, and the derived class will be known as the child class. The parent class has its own attributes and methods. While inheriting the child class will inherit the attributes and methods of the parent and also have its unique attributes and methods.  

For example, if you are taking the vehicle as a parent class with a colour attribute and speed method. If you are deriving a child-class car from vehicle class. Then, the car class will have unique attributes such as the number of tiers and mileage as a method. You can invoke the colour and speed methods from the car class since they are inherited.   

Finally, The above discussed are the OOPs concept of Java and their functionalities. You can attend a Java course online to extend your knowledge of Java.