Quiz Discussion

What is not type of inheritance?

• 1]

  Single inheritance

• 2]

  Double inheritance

• 3]

  Hierarchical inheritance

• 4]

   Multiple inheritance

Which of the following is used for implementing inheritance through an interface?

• 1]

  inherited

• 2]

  using

• 3]

  extends

• 4]

  implements

Which of this keyword must be used to inherit a class?

• 1]

  super

• 2]

  this

• 3]

  extent

• 4]

  extends

All classes in Java are inherited from which class?

• 1]

  java.lang.class

• 2]

  java.class.inherited

• 3]

  java.class.object

• 4]

  java.lang.object

What will be the output of the following Java program?

    class A 
    {
        int i;
        void display() 
        {
            System.out.println(i);
        }
    }    
    class B extends A 
    {
        int j;
        void display() 
        {
            System.out.println(j);
        }
    }    
    class inheritance_demo 
    {
        public static void main(String args[])
        {
            B obj = new B();
            obj.i=1;
            obj.j=2;   
            obj.display();     
        }
   }

• 1]

  0

• 2]

  1

• 3]

  2

• 4]

  Compilation Error

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

• 1]

  class B + class A {}

• 2]

  class B inherits class A {}

• 3]

  class B extends A {}

• 4]

  class B extends class A {}

What will be the output of the following Java program?

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

• 1]

  1 2
   

• 2]

  2 1

• 3]

  Runtime Error

• 4]

  Compilation Error

What would be the result if a class extends two interfaces and both have a method with same name and signature? Lets assume that the class is not implementing that method.

• 1]

  Runtime error

• 2]

  Compile time error

• 3]

  Code runs successfully

• 4]

  First called method is executed successfully

Using which of the following, multiple inheritance in Java can be implemented?

• 1]

  Interfaces

• 2]

  Multithreading

• 3]

  Protected methods

• 4]

  Private methods

Which of the following is used in implementing inheritance through class?

• 1]

  inherited

• 2]

  using

• 3]

  extends

• 4]

  implements