Java OOPs Concepts

Object means a real-world entity such as a pen, chair, table, computer, watch, etc. Object-Oriented Programming is a methodology or paradigm to design a program using classes and objects. It simplifies software development and maintenance by providing some concepts:

• Object
• Class
• Inheritance
• Polymorphism
• Abstraction
• Encapsulation

Object: Any entity that has state and behavior is known as an object. An Object can be defined as an instance of a class. An object contains an address and takes up some space in memory. Objects can communicate without knowing the details of each other's data or code. The only necessary thing is the type of message accepted and the type of response returned by the objects.

Class

Collection of objects is called class. It is a logical entity. A class can also be defined as a blueprint from which you can create an individual object. Class doesn't consume any space.

Inheritance

When one object acquires all the properties and behaviors of a parent object, it is known as inheritance. It provides code reusability. A new class can be created using already existing class.

Polymorphism

Having many forms is known as polymorphism. If one task is performed in different ways, it is known as polymorphism.

Abstraction

Hiding internal details and showing functionality is known as abstraction. In Java, we use abstract class and interface to achieve abstraction.

Encapsulation

Binding (or wrapping) code and data together into a single unit are known as encapsulation. A java class is the example of encapsulation.