Quiz Discussion

In order to restrict a variable of a class from inheriting to subclass, how variable should be declared?

• 1]

  Protected

• 2]

  Private

• 3]

  Public

• 4]

  Static

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

What will be the output of the following Java program?

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

• 1]

  2 2

• 2]

  3 3

• 3]

  2 3

• 4]

  3 2

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

• 1]

  inherited

• 2]

  using

• 3]

  extends

• 4]

  implements

If super class and subclass have same variable name, which keyword should be used to use super class?

• 1]

  super

• 2]

  this

• 3]

  upper

• 4]

  classname

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 {}

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

• 1]

  super

• 2]

  this

• 3]

  extent

• 4]

  extends

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

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

• 1]

  Interfaces

• 2]

  Multithreading

• 3]

  Protected methods

• 4]

  Private methods

What is not type of inheritance?

• 1]

  Single inheritance

• 2]

  Double inheritance

• 3]

  Hierarchical inheritance

• 4]

   Multiple inheritance