Question 1

Abstract methods are used when defining

Accepted Answer

A)  interface classes 
B)  derived classes 
C)  classes that have no constructor 
D)  arrays 
E)  classes that have no methods 
A)  interface classes 
B)  derived classes 
C)  classes that have no constructor 
D)  arrays 
E)  classes that have no methods A

Question 2

Consider a class named Name which has four instance data (all Strings): first, last, middle, title. Even though Name inherits the equals method from Object, it would make sense to override it. Why?

Accepted Answer

Object's version of equal compares two objects to see if they are the same Object, not if they are two Objects that share the same information. Two Name objects should be considered equal if they share the same first, middle, last and title Strings, not just if they are aliases for the same Object in memory. Therefore, the equals method should be overridden.

Question 3

All classes in Java are directly or indirectly subclasses of the __________ class.

Accepted Answer

A)  Wrapper 
B)  String 
C)  Reference 
D)  this 
E)  Object 
A)  Wrapper 
B)  String 
C)  Reference 
D)  this 
E)  Object E

Question 4

Which of the following is true about Java classes?

Accepted Answer

A)  All classes must have one parent but may have any number of children (derived or extended). 
B)  All classes must have one parent and may have a single child (derived or extended) but may have any number of parent classes. 
C)  All classes can have any number (zero or more) of parent classes and any number of children (derived or extended) classes. 
D)  All classes must have one parent and may have a single child (derived or extended) class. 
E)  All classes can have either zero or one parent class and any number of child (derived or extended) classes. 
A)  All classes must have one parent but may have any number of children (derived or extended). 
B)  All classes must have one parent and may have a single child (derived or extended) but may have any number of parent classes. 
C)  All classes can have any number (zero or more) of parent classes and any number of children (derived or extended) classes. 
D)  All classes must have one parent and may have a single child (derived or extended) class. 
E)  All classes can have either zero or one parent class and any number of child (derived or extended) classes.

Question 5

Example Code Ch 09-4
Given the following partial class definition:
public class A1
{
public int x;
private int y;
protected int z;
...
}
public class A2 extends A1
{
protected int a;
private int b;
...
}
public class A3 extends A2
{
private int q;
...
}
-Refer to Example Code Ch 09-4: Which of the following lists of instance data are accessible in class A2?

Accepted Answer

A)  x, y, z, a, b 
B)  x, y, z, a 
C)  x, z, a, b 
D)  z, a, b 
E)  a, b 
A)  x, y, z, a, b 
B)  x, y, z, a 
C)  x, z, a, b 
D)  z, a, b 
E)  a, b

Question 6

Java does not support multiple inheritance but some of the abilities of multiple inheritance are available by

Accepted Answer

A)  importing classes 
B)  implementing interfaces 
C)  overriding parent class methods 
D)  creating aliases 
E)  using public rather than protected or private modifiers 
A)  importing classes 
B)  implementing interfaces 
C)  overriding parent class methods 
D)  creating aliases 
E)  using public rather than protected or private modifiers

Question 7

The instruction super(); does which of the following?

Accepted Answer

A)  It calls the method super as defined in the current class. 
B)  It calls the method super as defined in the current class's parent class. 
C)  It calls the method super as defined in java.lang. 
D)  It calls the constructor as defined in the current class. 
E)  It calls the constructor as defined in the current class's parent class. 
A)  It calls the method super as defined in the current class. 
B)  It calls the method super as defined in the current class's parent class. 
C)  It calls the method super as defined in java.lang. 
D)  It calls the constructor as defined in the current class. 
E)  It calls the constructor as defined in the current class's parent class.

Question 8

Example Code Ch 09-1
Consider the following class hierarchy:
  
-Refer to Example Code Ch 09-1: If A, B, Y and Z all contain the same instance data d1, then d1 should be declared in X and inherited into Y, Z, A and B.

Accepted Answer

A) True 
 B)False

Question 9

If a programmer writes a class that he wants to be extended by another programmer, then this programmer must

Accepted Answer

A)  change private methods and instance data to be protected 
B)  change public methods and instance data to be protected 
C)  change all the methods to be protected 
D)  change the class to be protected 
E)  None of these; the programmer doesn't have to change anything 
A)  change private methods and instance data to be protected 
B)  change public methods and instance data to be protected 
C)  change all the methods to be protected 
D)  change the class to be protected 
E)  None of these; the programmer doesn't have to change anything

Question 10

Why is it a contradiction for an abstract method to be modified as final or static?

Accepted Answer

A final method cannot be overridden in d

Question 11

Explain the difference between using an imported class and extending a class.

Accepted Answer

An imported class lets you use someone e

Question 12

If you instantiate an abstract class, the class or object you wind up with

Accepted Answer

A)  is also an abstract class 
B)  is a normal class 
C)  is an interface 
D)  is a reference to an Object 
E)  you can't instantiate an abstract class 
A)  is also an abstract class 
B)  is a normal class 
C)  is an interface 
D)  is a reference to an Object 
E)  you can't instantiate an abstract class

Question 13

Example Code Ch 09-5
Consider the following class definition:
public class AClass
{
protected int x;
protected int y;
public AClass(int a, int b)
{
x = a;
y = b;
}
public int addEm()
{
return x + y;
}
public void changeEm()
{
x++;
y--;
}
public String toString()
{
return "" + x + " " + y;
}
}
-Refer to Example Code Ch 09-5: Which of the following would best redefine the toString method for BClass?

Accepted Answer

A)  public String toString(int z)
{
Return " " + x + " " + y + " " + z;
} 
B)  public String toString()
{
Return super.toString();
} 
C)  public String toString()
{
Return super.toString() + " " + z;
} 
D)  public String toString()
{
Return super.toString()+" " x+" "+y+" "+z;
} 
E)  public String toString()
{
Return " " + x + " + y + " " + z;
} 
A)  public String toString(int z)
{
Return " " + x + " " + y + " " + z;
} 
B)  public String toString()
{
Return super.toString();
} 
C)  public String toString()
{
Return super.toString() + " " + z;
} 
D)  public String toString()
{
Return super.toString()+" " x+" "+y+" "+z;
} 
E)  public String toString()
{
Return " " + x + " + y + " " + z;
}

Question 14

The JavaFX API offers the programmer controls that allow the user to pick colors or specific dates.

Accepted Answer

A) True 
 B)False

Question 15

You may use the super reserved word to access a parent class's private members.

Accepted Answer

A) True 
 B)False

Question 16

Assume a class Triangle has been defined. It has three instance data, Point p1, p2, p3. The class also has a constructor that receives the 3 Points and initializes p1, p2, p3, a toString method that outputs the 3 Points, and a computeSurfaceArea method that calculates the surface area of the Triangle (as an int value). We want to extend this class to represent a 3-dimensional Pyramid, which consists of 4 Points. Since the Pyramid will consist of, in essence, 4 triangles, computeSurfaceArea for the Pyramid will compute 4 times the surface area of the Triangle made up of 3 of those 4 Points. Write the Pyramid class to handle the difference(s) between a Pyramid and the previously defined Triangle. Assume the instance data of Triangle are protected and all methods are public. Also assume that the class Point has a toString method.

Accepted Answer

public class Pyramid extends Triangle
{

Question 17

A motorcycle inherits properties from both a bicycle and a car. Java does not permit multiple inheritance. Assume that Bicycle and Car have both been declared. Explain how you might go about implementing a Motorcycle as a derived class.

Accepted Answer

You should extend whichever class is clo

Question 18

In order to use a dialog box to display an alert to the user, you must include the AlertType class.

Accepted Answer

A) True 
 B)False

Question 19

Which of the following is an example of multiple inheritance?

Accepted Answer

A)  a computer can be a mainframe or a PC 
B)  a PC can be a desktop or a laptop 
C)  a laptop is both a PC and a portable device 
D)  a portable device is a lightweight device 
E)  Macintosh and IBM PC are both types of PCs 
A)  a computer can be a mainframe or a PC 
B)  a PC can be a desktop or a laptop 
C)  a laptop is both a PC and a portable device 
D)  a portable device is a lightweight device 
E)  Macintosh and IBM PC are both types of PCs

Question 20

If class AParentClass has a protected instance data x, and AChildClass is a derived class of AParentClass, then AChildClass can access x but cannot redefine x to be a different type.

Accepted Answer

A) True 
 B)False

Abstract methods are used when defining

Consider a class named Name which has four instance data (all Strings): first, last, middle, title. Even though Name inherits the equals method from Object, it would make sense to override it. Why?

All classes in Java are directly or indirectly subclasses of the __________ class.

Which of the following is true about Java classes?

Java does not support multiple inheritance but some of the abilities of multiple inheritance are available by

The instruction super(); does which of the following?

Example Code Ch 09-1 Consider the following class hierarchy: -Refer to Example Code Ch 09-1: If A, B, Y and Z all contain the same instance data d1, then d1 should be declared in X and inherited into Y, Z, A and B.

If a programmer writes a class that he wants to be extended by another programmer, then this programmer must

Why is it a contradiction for an abstract method to be modified as final or static?

Explain the difference between using an imported class and extending a class.

If you instantiate an abstract class, the class or object you wind up with

The JavaFX API offers the programmer controls that allow the user to pick colors or specific dates.

You may use the super reserved word to access a parent class's private members.

A motorcycle inherits properties from both a bicycle and a car. Java does not permit multiple inheritance. Assume that Bicycle and Car have both been declared. Explain how you might go about implementing a Motorcycle as a derived class.

In order to use a dialog box to display an alert to the user, you must include the AlertType class.

Which of the following is an example of multiple inheritance?

If class AParentClass has a protected instance data x, and AChildClass is a derived class of AParentClass, then AChildClass can access x but cannot redefine x to be a different type.

Introduction

Data and Expressions

Using Classes and Objects

Writing Classes

Conditionals and Loops

More Conditionals and Loops

Object-Oriented Design

Arrays

Polymorphism

Exceptions

Recursion

Collections

Filters

Exam 9: Inheritance

Abstract methods are used when defining

Consider a class named Name which has four instance data (all Strings): first, last, middle, title. Even though Name inherits the equals method from Object, it would make sense to override it. Why?

All classes in Java are directly or indirectly subclasses of the __________ class.

Which of the following is true about Java classes?

Java does not support multiple inheritance but some of the abilities of multiple inheritance are available by

The instruction super(); does which of the following?

Example Code Ch 09-1 Consider the following class hierarchy: -Refer to Example Code Ch 09-1: If A, B, Y and Z all contain the same instance data d1, then d1 should be declared in X and inherited into Y, Z, A and B.

If a programmer writes a class that he wants to be extended by another programmer, then this programmer must

Why is it a contradiction for an abstract method to be modified as final or static?

Explain the difference between using an imported class and extending a class.

If you instantiate an abstract class, the class or object you wind up with

The JavaFX API offers the programmer controls that allow the user to pick colors or specific dates.

You may use the super reserved word to access a parent class's private members.

A motorcycle inherits properties from both a bicycle and a car. Java does not permit multiple inheritance. Assume that Bicycle and Car have both been declared. Explain how you might go about implementing a Motorcycle as a derived class.

In order to use a dialog box to display an alert to the user, you must include the AlertType class.

Which of the following is an example of multiple inheritance?

If class AParentClass has a protected instance data x, and AChildClass is a derived class of AParentClass, then AChildClass can access x but cannot redefine x to be a different type.

Introduction

Data and Expressions

Using Classes and Objects

Writing Classes

Conditionals and Loops

More Conditionals and Loops

Object-Oriented Design

Arrays

Polymorphism

Exceptions

Recursion

Collections

Filters