Abstract Class

title: Abstract Class in Java description: Abstract class ka concept aur use

Abstract class ek incomplete class hai. Object create nahi ho sakta. Child class extend karke complete karta hai.

Syntax

java exampleWoHoTech

abstract class Shape {
    String color;

    Shape(String color) { this.color = color; }

    // Abstract method — subclass implement karega
    abstract double area();
    abstract double perimeter();

    // Concrete method
    void displayColor() {
        System.out.println("Color: " + color);
    }
}

Extend karna

java exampleWoHoTech

class Circle extends Shape {
    double radius;

    Circle(String color, double radius) {
        super(color);
        this.radius = radius;
    }

    @Override
    double area() { return Math.PI * radius * radius; }

    @Override
    double perimeter() { return 2 * Math.PI * radius; }
}

class Rectangle extends Shape {
    double width, height;

    Rectangle(String color, double w, double h) {
        super(color);
        this.width = w; this.height = h;
    }

    @Override
    double area() { return width * height; }

    @Override
    double perimeter() { return 2 * (width + height); }
}

Rules

abstract keyword use karo
Abstract class ka object nahi banta
Abstract methods ka body nahi hota
Child class sabhi abstract methods implement kare (ya khud abstract ho)
Constructor ho sakta hai

Use Case

Template Method Pattern mein use hota hai — common algorithm define karo, specific steps subclass mein.

title: Abstract Class in Java description: Abstract class ka concept aur use

Abstract class ek incomplete class hai. Object create nahi ho sakta. Child class extend karke complete karta hai.

Syntax

java exampleWoHoTech

abstract class Shape {
    String color;

    Shape(String color) { this.color = color; }

    // Abstract method — subclass implement karega
    abstract double area();
    abstract double perimeter();

    // Concrete method
    void displayColor() {
        System.out.println("Color: " + color);
    }
}

Extend karna

java exampleWoHoTech

class Circle extends Shape {
    double radius;

    Circle(String color, double radius) {
        super(color);
        this.radius = radius;
    }

    @Override
    double area() { return Math.PI * radius * radius; }

    @Override
    double perimeter() { return 2 * Math.PI * radius; }
}

class Rectangle extends Shape {
    double width, height;

    Rectangle(String color, double w, double h) {
        super(color);
        this.width = w; this.height = h;
    }

    @Override
    double area() { return width * height; }

    @Override
    double perimeter() { return 2 * (width + height); }
}

Rules

abstract keyword use karo
Abstract class ka object nahi banta
Abstract methods ka body nahi hota
Child class sabhi abstract methods implement kare (ya khud abstract ho)
Constructor ho sakta hai

Use Case

Template Method Pattern mein use hota hai — common algorithm define karo, specific steps subclass mein.

Abstract Class

Syntax

Extend karna

Rules

Use Case

Continue learning this concept

Abstract Class

Syntax

Extend karna

Rules

Use Case

Continue learning this concept