Java | Inheritance | The Inquisitive

Java - Inheritance

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Question 1

Which of these is correct way of inheriting class A by class B?

class B + class A {}

class B inherits class A {}

class B extends A {}

class B extends class A {}

Question 2

Which of these class is superclass of every class in Java?

Question 3

What is the output of the following code?

class Parent
{
    public int i;
    public int j;
    Parent() 
   {
        i = 1;
        j = 2;
    }
}    
class Child extends Parent
{
    int a;
    Child()
    {
        super();
    } 
}    
class Main
{
    public static void main(String args[])
    {
        Child obj = new Child();
        System.out.println(obj.i + " " + obj.j);
    }
}

Question 4

A class member declared protected becomes a member of subclass of which type?

Question 5

Which of these keywords can be used to prevent inheritance of a class?

Question 6

What is the output of the following code?

class Parent
{
    int i;
}    
class Child extends Parent
{
    int j;
    void display() 
    {
        super.i = j + 1;
        System.out.println(j + " " + i);
    }
}    
class inheritance 
{
    public static void main(String args[])
    {
        Child obj = new Child();
        obj.i=1;
        obj.j=2;   
        obj.display();     
    }
}