Four Design Principles

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In order for a system to be object oriented, it should adhere to certain design principles.

These design principles are:

Principle	Goal	Terms	Example
Abstraction	To reduce complexity by only showing relevant information	abstract class abstract method extend
Decomposition	To reduce complexity by separating problems	association aggregation composition
Encapsulation	To restrict access to data to protect them and reduce complexity	getter setter private protected public
Generalisation (Polymorphism/Inheritance)	To reduce complexity by having an umbrella term	superclass subclass interface implements extends

1. Abstraction
2. Encapsulation
3. Decomposition (Breaking objects down)
4. Generalisation (Polymorphism)

Object-Oriented Programming System

Object-oriented programming refers to the concept in high-level languages such as Java and Python that uses Objects and classes in their implementations. OOP has four major building blocks which are, Polymorphism, Encapsulation, Abstraction, and Inheritance.

There are other programming paradigms such as Procedural programming in which codes are written in sequentially. Python and Java are multi-paradigm high-level programming languages that means they support both OOP and procedural programming.