Java OCA OCP Practice Question 695

Question

Consider the following code: 

interface Cute{  } 
class Pet implements Cute  {  } 
class Cat extends Pet  {  } 
class Bat  {  } /*from   w  w w .  ja v  a2  s . co m*/

public class Main  { 
     
    public static void main (String [] args)  { 
        Cute f = new Cat (); 
        Cat e = new Cat (); 
        Bat b = new Bat (); 
         
        if (f instanceof Cute) System.out.println ("f is a Cute"); 
        if (e instanceof Pet) System.out.println ("e is a Pet"); 
        if (b instanceof Pet) System.out.println ("f is a Pet"); 
     } 
}

What will be printed when the above code is compiled and run?

Select 1 option

  • A. It will not compile.
  • B. It will throw an exception when run.
  • C. f is a Cute
  • e is a Pet
  • D. f is a Cute
  • E. e is a Pet 


Correct Option is  : A

Note

There is no compilation issue with b instanceof Cute because Cute is an interface.

It is possible for b to point to an object of a class that is a sub class of Bat and also implements Cute.

So the compiler doesn't complain.

If you make Bat class as final, b instanceof Cute will not compile because the compiler knows that it is not possible for b to point to an object of a class that implements Cute.




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