what are class in java

SYntax
class ClassName {
// variables
// methods
}
example of class
class Student {
int id;
String name;

void display() {
    System.out.println(id + " " + name);
}

}
Types of Classes in Java

1. Concrete Class

A normal class with full method implementations.

class Car {
    void run() {
        System.out.println("Car is running");
    }
}

**

1. Abstract Class

**Declared using abstract

Can have abstract methods and normal methods

Cannot create objects directly

abstract class Animal {
    abstract void sound();
}
abstract class Animal {
    abstract void sound();
}

1. Interface

Uses interface keyword

Only abstract methods (before Java 8)

Supports multiple inheritance

interface Vehicle {
    void move();
}

1. Final Class

Cannot be inherited

final class Bank {
    void rate() {
        System.out.println("Fixed rate");
    }
}

1. Nested Class

A class inside another class.

class Outer {
    class Inner {
        void show() {
            System.out.println("Inner class");
        }
    }
}

1. Anonymous Class

Class without a name, used for one-time use.

Runnable r = new Runnable() {
    public void run() {
        System.out.println("Running");
    }
};

1. POJO Class

Plain Old Java Object

No inheritance

Private variables

Public getters/setters

class Employee {
    private int id;

    public int getId() {
        return id;
    }
}