Java Module 2 Quiz

• hi hi

   

   

• hi world

• world world

• Compilation fails.

• An exception is thrown at runtime.

• 4

• 3

• 2

• 1

• D

• B

• A

• C,F

• E

Given:

11.  abstract class Vehicle { public int speed() { return 0; }

12.  class Car extends Vehicle { public int speed() { return 60; }

13.  class RaceCar extends Car { public int speed() { return 150; }

...

21.  RaceCar racer = new RaceCar();

22.  Car car = new RaceCar();

23.  Vehicle vehicle = new RaceCar();

24.  System.out.println(racer.speed() + ", " + car.speed()

25. + ", " + vehicle.speed());

What is the result?

• 0,0,0

• 150,60,0

• 150,150,150

• 60,0,150

Given:

5.  class Building { }

6.  public class Barn extends Building {

7.  public static void main(String[] args) {

8.  Building build1 = new Building();

9.  Barn barn1 = new Barn();

10.  Barn barn2 = (Barn) build1;

11.  Object obj1 = (Object) build1;

12.  String str1 = (String) build1;

13.  Building build2 = (Building) barn1;

14. }

15. }

Which is true?

• If line 10 is removed, the compilation succeeds.

   

• If line 13 is removed, the compilation succeeds.

• If line 11 is removed, the compilation succeeds.

• More than one line must be removed for compilation to succeed.

• If line 12 is removed, the compilation succeeds.

Given:

21.  class Money {

22.  private String country = "Canada";

23.  public String getC() { return country; }

24. }

25.  class Yen extends Money {

26.  public String getC() { return super.country; }

27. }

28.  public class Euro extends Money {

29.  public String getC(int x) { return super.getC(); }

30.  public static void main(String[] args) {

31.  System.out.print(new Yen().getC() + " " + new Euro().getC());

32. }

33. }

What is the result?

• null Canada

   

• Compilation fails due to an error on line 26.

• Canada null

• Canada Canada

• Compilation fails due to an error on line 29.

What is the maximum number of levels possible in a Multilevel Inheritance in Java?

• 32

• 16

• 8

• no limit

What type of inheritance does Java have?

• Multiple Inheritance

• Double Inheritance

• Class Inheritance 

• Single Inheritance

Given:

31.  class Foo {

32.  public int a = 3;

33.  public void addFive() { a += 5; System.out.print("f "); }

34. }

35.  class Bar extends Foo {

36.  public int a = 8;

37.  public void addFive() { this.a += 5; System.out.print("b " ); }

38. }

Invoked with:

Foo f = new Bar();

f.addFive();

System.out.println(f.a);

 

 

What is the result?

• b 3

• b 8

• f 3

• f 8

• f 13

Given:

5.  class Thingy { Meter m = new Meter(); }

6.  class Component { void go() { System.out.print("c"); } }

7.  class Meter extends Component { void go() { System.out.print("m"); } } 8.

9.  class DeluxeThingy extends Thingy {

10.  public static void main(String[] args) { 

11.  DeluxeThingy dt = new DeluxeThingy();

12.  dt.m.go();

13.  Thingy t = new DeluxeThingy();

14. t.m.go();

15. }

16. }

Which two are true? (Choose two.)

A.   The output is mm.

B.   The output is mc.

C.   Component is-a Meter.

D.   Component has-a Meter.

E.   DeluxeThingy is-a Component.

F.   DeluxeThingy has-a Component.

• C D

• A F

• B E

• E F

• A D