Abstraction in Java || Abstract Classes and Methods Frequently asked Interview Question| Code Decode

Learn how to make abstract classes and methods and the difference between abstract classes and interfaces!

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Abstract classes in java can be tricky at first... But SURELY you'll get it :) If you followed along :-)

#abstraction #abstractClassesAndMethod #abstractionInJava

[arpitsik]

Such an dedicated and helpful lady....She is suffering from ill, but still taking the classes n helping everyone out there. Hats Off to the dedeication Mam💯❤️

[anupshastri]

Blessed be this woman, she is ill and still tried her best to make the content as interesting as possible! hatsoff!

[alxx]

But i can implement Abstraction without interface or abstract class. Just a concrete class that hides certain functions and makes public other functions

[mdibrahimrazviks]

to whom were hiding internally details and showing functionality
This was the interview questions could you plz answer

[sonalgupta]

is there any real life application of making abstract class with all the methods which are concrete, i mean where can we use this concept?

[winiash]

How about when both interfaces have a same method name with different return types like int calculate() and Boolean calculate(). Won’t the class implementing it have an ambiguity then?

[aakash]

Still don't get what is the use of having an abstract class but there is no abstract method in it?

[chamanjain]

Hi, could you please explain how we achieve security, what we hide, from whom we hide it, and with examples in Java?
As I see abstraction has nothing to do with hiding and security. in my opinion, it's called abstraction because for abstract class we don't provide any concrete details. it is a template for the child's classes

Let's see an example

public abstract class Shape {

public abstract double getArea();

public abstract double getPerimeter();
}

class Circle extends Shape {
private double radius;

public Circle(double radius) {
this.radius = radius;
}

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

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

class Rectangle extends Shape {
private double width;
private double height;

public Rectangle(double width, double height) {
this.width = width;
this.height = height;
}

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

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

Now my client wants to use my area calculation app

public class Client {
public static void main(String[] args) {
Shape circle = new Circle(5);
Shape rectangle = new Rectangle(4, 6);

System.out.println("Area of circle: " + circle.getArea());
System.out.println("Perimeter of circle: " + circle.getPerimeter());

System.out.println("Area of rectangle: " + rectangle.getArea());
System.out.println("Perimeter of rectangle: " + rectangle.getPerimeter());
}
}

As we can see there is no security and nothing is hidden via abstraction
1) As instead of Shape class he can directly use Circle or Rectangle :
Circle circle = new Circle(5);
Rectangle rectangle = new Rectangle(4, 6);
2) The methods of Circle or Rectangle are public he can clearly see implementation: no hiding

Now if you make Circle or Rectangle abstract too then you my client can use functionality?

Please anyone clear my doubt

[theWorldOfIss]

You said Abstract class can't be instantiated then how it will create an instance 🧐 variable 😅

[arvinsuryavanshi]

Great explenetion but di, you suffering from cold take care

[praveenxsys]

Hi you are nice explain thank s provide the video