OOP Concept

OOP is an acronym for Object Oriented Programming Basically, OOP is a programming paradigm that represent data in form of REAL-WORLD Object.

Consider a CAR as REAL-WORLD Object. A car have features like:

• Colour
• Number of wheels
• Number of seats
• Weight
• ... etc

A car also does routines like:

• Starting and stopping the engine
• Steering right or left
• Beeping

In OOP, we define the aforementioned:

• Features as FIELDS
• Routines as METHODS or FUNCTIONS

As such, it's safe to say that CAR is a CLASS of OBJECTS that has the aforementioned features and does the aforementioned routines.

Java

Java is an OOP language that allows us to represent our data in form of REAL-WORLD objects.

Classes

The container of any object that we want to represent.

Fields

Our object's traits and features like: weight, colour, name, age ... etc.

Methods or Functions

The routines our object does like: sleeping, waking up, singing ... etc.

Java Syntax

A java class has this syntax

class Class_Name
{
  
}

A car class would be represented like this:

class Car
{
  
}

A java method has this syntax

type-of-returned-data method_name(arguments)
{
 return some-data; 
}

A car method that converts speed from M/H to KM/H would be represented like this:

class Car
{
  int m_to_km(int speed)
  {
    return (speed / 1000);
  }
}

int: is the data type that represents numerical values int speed: is an argument to the method, an argument's definition consists of argument type followed by its name like: int speed, char a