Java Classes

# Introduction

• Java is an object-oriented programming (OOP) language, and at the heart of object-oriented programming are classes. A class is one of the most fundamental concepts in Java because it provides the blueprint for creating objects that represent real-world entities.

• Every Java application is built using classes. Whether you're creating a simple calculator, a banking system, a game, or a large enterprise application, classes are used to organize code, define data, and implement behavior. They help developers write code that is modular, reusable, maintainable, and easier to understand.

• A class groups together data (fields) and behavior (methods) into a single unit. Instead of scattering related variables and functions throughout a program, Java encourages developers to encapsulate them within classes. This approach improves code organization, reduces duplication, and makes software easier to extend and maintain.

• For example, consider a Car. A car has characteristics such as its brand, model, color, and speed, and it can perform actions like starting, stopping, accelerating, and braking. In Java, these characteristics become fields, while the actions become methods inside a Car class.

`public class Car {

// Fields (State)
String brand;
String model;
int year;

// Method (Behavior)
public void start() {
    System.out.println("The car has started.");
}

}`

In this example:

• **Car **is the class name.
• brand, model, and **year **are fields that store information about a car.
• start() is a method that defines an action the car can perform.