Question 1

Write a single statement that creates a DecimalFormat object that formats numbers to 2 decimal places.

Accepted Answer

The answer of Write a single statement that creates a...

Question 2

Suppose a Random object has been created called generator. Write a single statement that generates a random number in the range 73 to 100.

Accepted Answer

The answer of Suppose a Random object has been created...

Question 3

Which of the following represents the proper way to create a NumberFormat object that formats numbers as percentages?

Accepted Answer

A)  NumberFormat fmt = new NumberFormat(%); 
B)  NumberFormat fmt = new NumberFormat("%"); 
C)  NumberFormat fmt = NumberFormat.getPercentInstance(); 
D)  NumberFormat fmt = new PercentNumberFormat(); 
E)  none of the above

Question 4

Which of the following best describes what happens when an object no longer has any references pointing to it?

Accepted Answer

A)  The object is overwritten the next time the new operator is called. 
B)  The object is overwritten the next time the new operator is called using the same class. 
C)  The object is immediately deleted from memory. 
D)  The object is marked as garbage and its associated memory is freed when the garbage collector runs. 
E)  The object stays in memory for the remainder of the programs execution.

Question 5

Multiple reference variables can refer to the same object.

Accepted Answer

A) True 
 B)False

Question 6

Suppose we have a String object referenced by a variable called listing. Suppose we want a new String object that consists of the first 5 characters in listing. Which of the following lines of code will achieve this?

Accepted Answer

A)  String prefix = listing.front(5); 
B)  String prefix = listing.front(6); 
C)  String prefix = listing.substring(1,5); 
D)  String prefix = listing.substring(0,5); 
E)  String prefix = listing.firstChars(5);

Question 7

Consider the following snippet of code: Random generator = new Random();
Int randNum = generator.nextInt(20) + 1;
Which of the following will be true after these lines are executed?

Accepted Answer

A)  randNum will hold a number between 1 and 20 inclusive. 
B)  randNum will hold a number between 0 and 20 inclusive. 
C)  randNum will hold a number between 1 and 21 inclusive. 
D)  these lines will not be executed because a compiler error will result. 
E)  none of the above

Question 8

When there are no references to an object, the object is marked as garbage and is automatically removed from memory using Java's automatic garbage collection feature.

Accepted Answer

A) True 
 B)False

Question 9

____________________ is the automatic conversion between a primitive value and a corresponding wrapper object.

Accepted Answer

A)  Generating 
B)  Aliasing 
C)  Number formatting 
D)  Static invocation 
E)  Autoboxing

Question 10

What is output by the following code fragment?
String hello = new String("Hello World!");
hello = hello.replace('H', 'W');
hello = hello.replace('W', 'H');
System.out.println(hello);

Accepted Answer

The answer of What is output by the following code...

Question 11

Write a declaration for an enumerated type that represents the months of the year.

Accepted Answer

The answer of Write a declaration for an enumerated type...

Question 12

When called with integer parameter n, the nextInt() method of the Random class will return a randomly generated integer between 0 and n.

Accepted Answer

A) True 
 B)False

Question 13

The new operator is used to access an objects methods.

Accepted Answer

A) True 
 B)False

Question 14

Write a short program that allows the user to enter the base and height of a triangle and outputs the hypotenuse, formatted to three decimal places.

Accepted Answer

The answer of Write a short program that allows the...

Question 15

Write a statement that computes the square root of a variable called discriminant and stores the value in a variable called result.

Accepted Answer

The answer of Write a statement that computes the square...

Question 16

String objects can be changed after instantiation.

Accepted Answer

A) True 
 B)False

Question 17

The System.out.printf() method is an alternative way to output information in Java.

Accepted Answer

A) True 
 B)False

Question 18

What is the range of integers that will be generated by the following expression?
generator.nextInt(15) + 5;

Accepted Answer

The answer of What is the range of integers that...

Question 19

Which of the following classes include the getCurrencyInstance() method?

Accepted Answer

A)  String 
B)  NumberFormat 
C)  DecimalFormat 
D)  Math 
E)  none of the above

Question 20

Write an expression that computes 12 raised to the power 4.3 and store the result in a double called result.

Accepted Answer

The answer of Write an expression that computes 12 raised...

Exam 3: Using Classes and Objects

Write a single statement that creates a DecimalFormat object that formats numbers to 2 decimal places.

Suppose a Random object has been created called generator. Write a single statement that generates a random number in the range 73 to 100.

Which of the following represents the proper way to create a NumberFormat object that formats numbers as percentages?

Which of the following best describes what happens when an object no longer has any references pointing to it?

Multiple reference variables can refer to the same object.

Suppose we have a String object referenced by a variable called listing. Suppose we want a new String object that consists of the first 5 characters in listing. Which of the following lines of code will achieve this?

Consider the following snippet of code: Random generator = new Random() ; Int randNum = generator.nextInt(20) + 1; Which of the following will be true after these lines are executed?

When there are no references to an object, the object is marked as garbage and is automatically removed from memory using Java's automatic garbage collection feature.

____________________ is the automatic conversion between a primitive value and a corresponding wrapper object.

What is output by the following code fragment? String hello = new String("Hello World!"); hello = hello.replace('H', 'W'); hello = hello.replace('W', 'H'); System.out.println(hello);

Write a declaration for an enumerated type that represents the months of the year.

When called with integer parameter n, the nextInt() method of the Random class will return a randomly generated integer between 0 and n.

The new operator is used to access an objects methods.

Write a short program that allows the user to enter the base and height of a triangle and outputs the hypotenuse, formatted to three decimal places.

Write a statement that computes the square root of a variable called discriminant and stores the value in a variable called result.

String objects can be changed after instantiation.

The System.out.printf() method is an alternative way to output information in Java.

What is the range of integers that will be generated by the following expression? generator.nextInt(15) + 5;

Which of the following classes include the getCurrencyInstance() method?

Write an expression that computes 12 raised to the power 4.3 and store the result in a double called result.