1. Can you extend an abstract class? In what situation can you not inherit/extend a class?...

1. Can you extend an abstract class? In what situation can you not inherit/extend a class?

2. Can you still make it an abstract class if a class does not have any abstract methods?

Solutions

Expert Solution

First of all, let's understand the meaning of Abstract class.

Abstract class:

An abstract class is a class that is declared abstract.
It may or may not include abstract methods.
It cannot be instantiated, but they can be subclassed.

Answer - Question: 1

Yes, we can extend an abstract class.

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


public class Dog extends Animal{

   public void sound(){
        System.out.println("Woof");
   }
}

Any class inheriting the current class must either override the abstract method or declare itself as abstract.
So, if we are not overriding, we can't inherit/extend.

Answer - Question: 2

Yes, we can have an abstract class without Abstract Methods as both are independent concepts.
Declaring a class abstract means that it can not be instantiated on its own.
Declaring a method abstract means that Method will be defined in the subclass.

public abstract class AbstractClass{

    public String nonAbstractMethod1(int a, int b){
        int c = a + b;
        return c;
    }

    public static void nonAbstractMethod2(int c){
        System.out.println("Value of c is "+ c);
    }
}

Please let me know in the comments in case of any confusion. Also, please upvote if you like.

venereology answered 1 year ago

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