OOPs Concepts in Java

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In this article, you’ll learn about OOPs Concepts in Java such as class, object, inheritance, Encapsulation, hiding, polymorphism.

OOP meaning “Object Oriented Programming” is a popularly known and widely used concept in modern programming languages like Java.

General OOPs concepts in Java

1) Class in Java

The class is one of the Basic concepts of OOPs which is a group of similar entities. It is only a logical component and not the physical entity. Lets understand this one of the OOPs Concepts with example, if you had a class called “Expensive Cars” it could have objects like Mercedes, BMW, Toyota, etc. Its properties(data) can be price or speed of these cars. While the methods may be performed with these cars are driving, reverse, braking etc.

2) Object in Java

An object can be defined as an instance of a class, and there can be multiple instances of a class in a program. An Object is one of the Java OOPs concepts which contains both the data and the function, which operates on the data. For example – chair, bike, marker, pen, table, car, etc.

3) Inheritance in Java

Inheritance is one of the Basic Concepts of OOPs in which one object acquires the properties and behaviors of the parent object. It’s creating a parent-child relationship between two classes. It offers robust and natural mechanism for organizing and structure of any software.

4) Polymorphism in Java

Polymorphism refers to one of the OOPs concepts in Java which is the ability of a variable, object or function to take on multiple forms. For example, in English, the verb run has a different meaning if you use it with a laptop, a foot race, and business. Here, we understand the meaning of run based on the other words used along with it. The same also applied to Polymorphism.

5) Abstraction in Java

Abstraction is one of the OOP Concepts in Java which is an act of representing essential features without including background details. It is a technique of creating a new data type that is suited for a specific application. Lets understand this one of the OOPs Concepts with example, while driving a car, you do not have to be concerned with its internal working. Here you just need to concern about parts like steering wheel, Gears, accelerator, etc.

6) Encapsulation in Java

Encapsulation is one of the best Java OOPs concepts of wrapping the data and code. In this OOPs concept, the variables of a class are always hidden from other classes. It can only be accessed using the methods of their current class. For example – in school, a student cannot exist without a class.

7) Association in Java

Association is a relationship between two objects. It is one of the OOP Concepts in Java which defines the diversity between objects. In this OOP concept, all objects have their separate lifecycle, and there is no owner. For example, many students can associate with one teacher while one student can also associate with multiple teachers.

8) Aggregation in Java

In this technique, all objects have their separate lifecycle. However, there is ownership such that child object can’t belong to another parent object. For example consider class/objects department and teacher. Here, a single teacher can’t belong to multiple departments, but even if we delete the department, the teacher object will never be destroyed.

9) Composition in Java

Composition is a specialized form of Aggregation. It is also called “death” relationship. Child objects do not have their lifecycle so when parent object deletes all child object will also delete automatically. For that, let’s take an example of House and rooms. Any house can have several rooms. One room can’t become part of two different houses. So, if you delete the house room will also be deleted.

Advantages of OOPs (Object-Oriented Programming)

• OOPs Concepts in Java offer easy to understand and a clear modular structure for programs.
• Objects created for Object-Oriented Programs can be reused in other programs. Thus it saves significant development cost.
• Large programs are difficult to write, but if the development and designing team follow OOPS concepts, then they can better design with minimum flaws.
• It enhances program modularity because every object exists independently.