Question 1

Consider the following two lines of code. What can you say about s1 and s2?
String s1 = "testing" + "123";
String s2 = new String("testing 123");

Accepted Answer

A)  s1 and s2 are both references to the same String object 
B)  the line declaring s2 is legal Java; the line declaring s1 will produce a syntax error 
C)  s1 and s2 are both references to different String objects 
D)  s1 and s2 will compare "equal" 
E)  none of the above 
A)  s1 and s2 are both references to the same String object 
B)  the line declaring s2 is legal Java; the line declaring s1 will produce a syntax error 
C)  s1 and s2 are both references to different String objects 
D)  s1 and s2 will compare "equal" 
E)  none of the above C

Question 2

What is the advantage of putting an image in a JLabel instance?

Accepted Answer

A)  It becomes part of the component and is laid out automatically 
B)  It becomes part of the container and is automatically scaled 
C)  Although it becomes part of the instance, it still must be drawn separately 
D)  The runtime efficiency is greatly improved 
E)  None of the above 
A)  It becomes part of the component and is laid out automatically 
B)  It becomes part of the container and is automatically scaled 
C)  Although it becomes part of the instance, it still must be drawn separately 
D)  The runtime efficiency is greatly improved 
E)  None of the above A

Question 3

Java.text's NumberFormat class includes methods that

Accepted Answer

A)  allow you to format currency 
B)  allow you to format percentages 
C)  round their display during the formatting process 
D)  truncate their display during the formatting process 
E)  A, B, C, but not D 
A)  allow you to format currency 
B)  allow you to format percentages 
C)  round their display during the formatting process 
D)  truncate their display during the formatting process 
E)  A, B, C, but not D E

Question 4

Which of the following will yield a pseudorandom number in the range [ -5, +5 ) given the following: Random gen = new Random( );

Accepted Answer

A)  gen.nextFloat( ) * 5 
B)  gen.nextFloat( ) * 10 - 5 
C)  gen.nextFloat( ) * 5 - 10 
D)  gen.nextInt( ) * 10 - 5 
E)  gen.nextInt(10) - 5 
A)  gen.nextFloat( ) * 5 
B)  gen.nextFloat( ) * 10 - 5 
C)  gen.nextFloat( ) * 5 - 10 
D)  gen.nextInt( ) * 10 - 5 
E)  gen.nextInt(10) - 5

Question 5

What is the function of the dot operator?

Accepted Answer

A)  It serves to separate the integer portion from the fractional portion of a floating point number 
B)  It allows one to access the data within an object when given a reference to the object 
C)  It allows one to invoke a method within an object when given a reference to the object 
D)  It is used to terminate commands (much as a period terminates a sentence in English) 
E)  Both B and C are correct 
A)  It serves to separate the integer portion from the fractional portion of a floating point number 
B)  It allows one to access the data within an object when given a reference to the object 
C)  It allows one to invoke a method within an object when given a reference to the object 
D)  It is used to terminate commands (much as a period terminates a sentence in English) 
E)  Both B and C are correct

Question 6

You may use the String replace( ) method to remove characters from a String.

Accepted Answer

A) True 
 B)False

Question 7

The String class' compareTo method

Accepted Answer

A)  compares two string in a case-independent manner 
B)  yields True or false 
C)  yields 0 if the two strings are identical 
D)  returns 1 if the first string comes lexically before the second string 
E)  none of the above 
A)  compares two string in a case-independent manner 
B)  yields True or false 
C)  yields 0 if the two strings are identical 
D)  returns 1 if the first string comes lexically before the second string 
E)  none of the above

Question 8

A containment hierarchy is

Accepted Answer

A)  a collection of relationships among panels, all at the same level 
B)  a nested collection of relationships among containers 
C)  a nested collection of relationships among applets 
D)  a collection of relationships among frames, usually at different levels 
E)  none of the above 
A)  a collection of relationships among panels, all at the same level 
B)  a nested collection of relationships among containers 
C)  a nested collection of relationships among applets 
D)  a collection of relationships among frames, usually at different levels 
E)  none of the above

Question 9

Which properties are True of String objects?

Accepted Answer

A)  Their lengths never change 
B)  The shortest string has zero length 
C)  Individual characters within a String may be changed using the replace method 
D)  The index of the first character in a string is one 
E)  Only A and B are True 
A)  Their lengths never change 
B)  The shortest string has zero length 
C)  Individual characters within a String may be changed using the replace method 
D)  The index of the first character in a string is one 
E)  Only A and B are True

Question 10

In the StringMutation program shown in Listing 3.1, if phrase is initialized to "Einstein" what will Mutation #3 yield if Mutation #1: mutation1 = phrase.concat(".")?

Accepted Answer

A)  Einstein. 
B)  EINSTEIN. 
C)  XINSTXIN. 
D)  einstein. 
E)  xinstxin. 
A)  Einstein. 
B)  EINSTEIN. 
C)  XINSTXIN. 
D)  einstein. 
E)  xinstxin.

Question 11

The Random class' setSeed( ) method allows you to restart the pseudo-random number sequence.

Accepted Answer

A) True 
 B)False

Question 12

Given two String variables, s1 and s2, is it possible for (s1 != s2) to be True while (s1.equals(s2)) is also True?
 Why or why not?

Accepted Answer

The condition (s1 != s2) means that s1 a

Question 13

What will be displayed by this command: System.out.println(Math.pow(3, 3-1));

Accepted Answer

A)  9 
B)  8 
C)  6 
D)  4 
E)  27 
A)  9 
B)  8 
C)  6 
D)  4 
E)  27

Question 14

An API is

Accepted Answer

A)  an Abstract Programming Interface 
B)  an Application Programmer's Interface 
C)  an Application Programming Interface 
D)  an Abstract Programmer's Interface 
E)  an Absolute Programming Interface 
A)  an Abstract Programming Interface 
B)  an Application Programmer's Interface 
C)  an Application Programming Interface 
D)  an Abstract Programmer's Interface 
E)  an Absolute Programming Interface

Question 15

Write a method to extract the initial from the first name.

Accepted Answer

firstIniti

Question 16

All the methods in the Math class are declared to be static.

Accepted Answer

A) True 
 B)False

Question 17

An "alias" is when

Accepted Answer

A)  two different reference variables refer to the same physical object 
B)  two different numeric variables refer to the same physical object 
C)  two different numeric variables contain identical values 
D)  two variables have the same names 
E)  none of the above 
A)  two different reference variables refer to the same physical object 
B)  two different numeric variables refer to the same physical object 
C)  two different numeric variables contain identical values 
D)  two variables have the same names 
E)  none of the above

Question 18

What is the function of a frame's pack method?

Accepted Answer

A)  It deletes unused storage 
B)  It forces orphan objects to be reclaimed by the garbage collector 
C)  It sets the size appropriately for display 
D)  It forces the frame contents to be up-left justified 
E)  None of the above 
A)  It deletes unused storage 
B)  It forces orphan objects to be reclaimed by the garbage collector 
C)  It sets the size appropriately for display 
D)  It forces the frame contents to be up-left justified 
E)  None of the above

Question 19

A JPanel can be added to a JFrame to form a GUI. In order to place other GUI components such as JLabels and Buttons into the JFrame, which of the following messages is passed to the JPanel?

Accepted Answer

A)  insert 
B)  include 
C)  get 
D)  getContentPane 
E)  add 
A)  insert 
B)  include 
C)  get 
D)  getContentPane 
E)  add

Question 20

When comparing any primitive type of variable, == should always be used to test to see if two values are equal.

Accepted Answer

A) True 
 B)False

Consider the following two lines of code. What can you say about s1 and s2? String s1 = "testing" + "123"; String s2 = new String("testing 123");

What is the advantage of putting an image in a JLabel instance?

Java.text's NumberFormat class includes methods that

Which of the following will yield a pseudorandom number in the range [ -5, +5 ) given the following: Random gen = new Random( );

What is the function of the dot operator?

You may use the String replace( ) method to remove characters from a String.

The String class' compareTo method

A containment hierarchy is

Which properties are True of String objects?

In the StringMutation program shown in Listing 3.1, if phrase is initialized to "Einstein" what will Mutation #3 yield if Mutation #1: mutation1 = phrase.concat(".")?

The Random class' setSeed( ) method allows you to restart the pseudo-random number sequence.

Given two String variables, s1 and s2, is it possible for (s1 != s2) to be True while (s1.equals(s2)) is also True? Why or why not?

What will be displayed by this command: System.out.println(Math.pow(3, 3-1));

An API is

Write a method to extract the initial from the first name.

All the methods in the Math class are declared to be static.

An "alias" is when

What is the function of a frame's pack method?

A JPanel can be added to a JFrame to form a GUI. In order to place other GUI components such as JLabels and Buttons into the JFrame, which of the following messages is passed to the JPanel?

When comparing any primitive type of variable, == should always be used to test to see if two values are equal.

Introduction

Data and Expressions

Writing Classes

Conditionals and Loops

More Conditionals and Loops

Object-Oriented Design

Arrays

Inheritance

Polymorphism

Exceptions

Recursion

Collections

Filters

Exam 3: Using Classes and Objects

Consider the following two lines of code. What can you say about s1 and s2? String s1 = "testing" + "123"; String s2 = new String("testing 123");

What is the advantage of putting an image in a JLabel instance?

Java.text's NumberFormat class includes methods that

Which of the following will yield a pseudorandom number in the range [ -5, +5 ) given the following: Random gen = new Random( );

What is the function of the dot operator?

You may use the String replace( ) method to remove characters from a String.

The String class' compareTo method

A containment hierarchy is

Which properties are True of String objects?

In the StringMutation program shown in Listing 3.1, if phrase is initialized to "Einstein" what will Mutation #3 yield if Mutation #1: mutation1 = phrase.concat(".")?

The Random class' setSeed( ) method allows you to restart the pseudo-random number sequence.

Given two String variables, s1 and s2, is it possible for (s1 != s2) to be True while (s1.equals(s2)) is also True? Why or why not?

What will be displayed by this command: System.out.println(Math.pow(3, 3-1));

An API is

Write a method to extract the initial from the first name.

All the methods in the Math class are declared to be static.

An "alias" is when

What is the function of a frame's pack method?

A JPanel can be added to a JFrame to form a GUI. In order to place other GUI components such as JLabels and Buttons into the JFrame, which of the following messages is passed to the JPanel?

When comparing any primitive type of variable, == should always be used to test to see if two values are equal.

Introduction

Data and Expressions

Writing Classes

Conditionals and Loops

More Conditionals and Loops

Object-Oriented Design

Arrays

Inheritance

Polymorphism

Exceptions

Recursion

Collections

Filters