Unit 1

A Painter object called myPainter is facing north. Consider the following code segment.

while (!myPainter.isFacingSouth()) { myPainter.turnLeft(); }

myPainter.turnLeft();

myPainter.turnLeft();

The effect of this code is that the myPainter object is now:

• facing north

• facing east

• facing west

• facing south

Which of the following is a TRUE statement about constructors in Java?

A.   The constructor contains all of the methods that an object can utilize.

B.   Constructors should be made private to keep all information safe and secure.

C.   The constructor should not have the same name as the class.

D.   In inheritance, the parent class should always contain the keyword super.

E.   The constructor is used to create objects of a class.

• A

• D

• C

• E

• B

A Painter object called myPainter is initially facing east. Consider the following code segment.

while (myPainter.canMove()) { myPainter.move(); }

After the loop has terminated, which of the following MUST be true?

• The Painter object is blocked from moving north.

• The Painter object is blocked from moving east.

• The Painter object is blocked from moving west.

• The Painter object is blocked from moving south.

Which of the following are inherited when one class extends another?

I. private attributes

II. public constructors

III. public methods

A.   I only

B.   III only

C.   I and II

D.   II and III

E.   I, II, and III

• A

• B

• C

• D

• E

Consider the following code segment.

if (myPainter.isFacingNorth()) {

myPainter.move();

myPainter.move(); }

if (!myPainter.isFacingNorth()) {

myPainter.move();

myPainter.paint("green"); }

Which of the following is equivalent?

• 
• 
• 
• 

Given a Painter object called myPainter, which method call would cause a syntax error?

• myPainter.move();

• myPainter.turnLeft();

• myPainter.takePaint();

• myPainter.canMove();

• myPainter.paint();

Which of the following correctly instantiates a new Painter object?

• Painter daVinci = new Painter();

• daVinci Painter = new Painter();

• Painter daVinci = Painter();

• Painter() daVinci = new Painter;

• Painter daVinci = Painter;

Consider the following code segment.

public class PainterPlus extends Painter { public PainterPlus(){

super(); }

public void turnRight() {

turnLeft();

turnLeft();

turnLeft(); } }

What is the name of the superclass?

• PainterPlus

• Painter

• SuperPainter

• MyNeighborhood

• turnRight()

Fill in the blank. Inheritance represents a/an ___ relationship.

• has-a

• has-many

• is-a

• is-many

• none of the above

Consider the following class headers.

public class Food {

//implementation not shown }

public class Dessert extends Food {

//implementation not shown }

public class Cookie extends Dessert {

//implementation not shown }

Which statement below is true regarding the class declarations?

I. Food is a subclass of Cookie

II. Dessert is a superclass of Cookie

III. Cookie is a subclass of Dessert

IV. Cookie is a superclass of Food

• I only

• III only

• I and II

• II and IV

• II and III