Dive deep into how OOP works in Java. Learn to write cleaner, more reusable code using OOP principles.

Java for Programmers

Object Oriented Programming (OOP) is a programming paradigm popular for large and complex systems. In this. module, dive deep into how OOP works in Java. Learn to write cleaner, more reusable code using OOP principles.

Object Oriented Programming

## What are default methods?
Before Java 8, we could only declare abstract methods in an interface. However, Java 8 introduced the concept of default methods. **Default methods are methods that can have a body**. The most important use of default methods in interfaces is to provide additional functionality to a given type without breaking down the implementing classes.

Before Java 8, if a new method was introduced in an interface then all the implementing classes used to break. We would need to provide the implementation of that method in all the implementing classes. 

However, sometimes methods have only single implementation and there is no need to provide their implementation in each class. 
In that case, we can declare that method as a default in the interface and provide its implementation in the interface itself. 

## Syntax of default methods
Let's understand the syntax of default methods through an example.
Here, we have an interface with one abstract and one default method:


# What are default methods?
Before Java 8, we could only declare abstract methods in an interface. However, Java 8 introduced the concept of default methods. **Default methods are methods that can have a body**. The most important use of default methods in interfaces is to provide additional functionality to a given type without breaking down the implementing classes.

Before Java 8, if a new method was introduced in an interface then all the implementing classes used to break. We would need to provide the implementation of that method in all the implementing classes. 

However, sometimes methods have only single implementation and there is no need to provide their implementation in each class. 
In that case, we can declare that method as a default in the interface and provide its implementation in the interface itself. 

# Syntax of default methods
Let's understand the syntax of default methods through an example.
Here, we have an interface with one abstract and one default method:


Let's learn what default methods in interfaces are and why they were introduced in Java 8.

Classes and Objects

Data Hiding

Inheritance

Polymorphism

Abstract Classes and Interfaces

Aggregation and Composition

Default Methods in interfaces

What are default methods?