(6-7)

Question 1

Data hiding, which means critical data stored inside the object is protected from code outside the object, is accomplished in Java by:

Answer 1

using the private access specifier on the class fields

Question 2

The scope of a public instance field is:

Answer 2

the instance methods and methods outside the class

Question 3

Instance methods do not have the key word static in their headers

Answer 3

True

Question 4

A method that stores a value in a class’s field or in some other way changes the value of a field is known as a mutator method

Answer 4

True

Question 5

The java.lang package is automatically imported into all Java programs

Answer 5

True

Question 6

A method that gets a value from the class’s field but does not change it is known as a mutator method

Answer 6

False

Question 7

For the following code, which statement is NOT true?

public class Circle
{
private double radius;
private double x;
private double y;
}

Answer 7

Y is available to code that is written outside the Circle class

Question 8

It is common practice in object-oriented programming to make all of a class’s:

Answer 8

fields private

Question 9

For the following code which statement is NOT true?

public class Sphere
{
private double radius;
public double x;
private double y;
private double z;
}

Answer 9

Z is available to code that is written outside the circle class

Question 10

Java allows you create objects of this class in the same way you would create primitive values

Answer 10

String

Question 11

The public access specifier for a field indicates that the attribute may not be accessed by statements outside the class

Answer 11

False

Question 12

A class in not an object, but description of an object

Answer 12

True

Question 13

An object can store data

Answer 13

True

Question 14

A class specifies _________ and ______ that a particular type of object has

Answer 14

fields; methods

Question 15

Look at the following statement:

import.java.util.*;

This is an example of:

Answer 15

A wildcard import

Question 16

A constructor:

Answer 16

has the same name as the class

Question 17

Which of the following statements will create a reference, str, to the String, “Hello, World”?

Answer 17

String str = “Hello, World”;

Question 18

Which of the following are classes from the Java API?

Answer 18

Scanner, Random, and PrintWriter

Question 19

You should not define a class field that is dependent upon the values of other class fields:

Answer 19

in order to avoid having stale data

Question 20

Methods that operate on an object’s fields are called:

Answer 20

instance methods

Question 21

Which of the following will create a reference, str, to the string, “Hello, World?”

1. String str = new String(“Hello World);
2. String str = “Hello, world”;

Answer 21

Both 1 and 2

Question 22

Class objects normally have __________ that perform useful operations on their data, but primitive values do not.

Answer 22

methods

Question 23

One or more objects may be created from a(n)

Answer 23

class

Question 24

What is stored by a reference variable?

Answer 24

A memory address

Question 25

Instance methods do not have this key word in their headers:

Answer 25

Static

Question 26

A constructor is a method that:

Answer 26

performs initialization or setup operation

Question 27

An access specifier indicates how the class may be accessed

Answer 27

True

Question 28

The following package is automatically imported into all Java programs

Answer 28

java.lang

Question 29

In UML diagrams, this symbol indicates that a member is public

Answer 29

+

Question 30

Given the following code what will be the final amount when it is displayed?

Answer 30

522.00

Question 31

In your textbook the general layout of a UML diagram is a box that is divided into three sections. The top section has the ________; the middle section holds ___________; the bottom section holds __________

Answer 31

class name; attributes or fields; methods

Question 32

What does the following UML diagram entry mean? + setHeight(h : double) : void

Answer 32

A public method with a parameter of data type double that does not return a value

Question 33

Overloading means multiple methods in the same class:

Answer 33

have the same name, but different parameter lists

Question 34

In a UML diagram to indicate the data type of a variable enter:

Answer 34

the variable name followed by a colon and the data type

Question 35

The term "no-arg-constructor" is applied to any constructor that does not accept arguments

Answer 35

True

Question 36

When an object is passed as an argument to a method, what is passed into the method's parameter variable?

Answer 36

the object's memory address

Question 37

Look at the following statement: import java.util.Scanner; This is an example of:

Answer 37

an explicit import

Question 38

The scope of a private instance field is:

Answer 38

the instance methods of the same class

Question 39

Another term for an object of a class is:

Answer 39

instance

Question 40

A constructor is a method that is automatically called when an object is created:

Answer 40

True

Question 41

What will be the value of x[1] after the following code is executed? int[] x = {22, 33, 44}; arrayProcess(x); public static void arrayProcess(int[] a) { for (int k = 0; k < 3; k++) { a[k] = a[k] + 5; } }

Answer 41

38

Question 42

What would be the results of the following code? final int SIZE = 25; int[] array1 = new int[SIZE]; // Code that will put values in array1 int value = 0; for (int a = 0; a <= array1.length; a++) { value += array1[a]; }

Answer 42

This will cause the program to show an error

Question 43

What will be the result of executing the following code? int[] x = {0, 1, 2, 3, 4, 5};

Answer 43

An array of 6 values ranging from 0 through 5 and referenced by the variable x will be created

Question 44

Declaring an array reference variable does not create an array.

Answer 44

True

Question 45

Which of the following statements are TRUE about the following code? final int ARRAY_SIZE = 10; long[] array1 = new long[ARRAY_SIZE];

Answer 45

- Declares array1 to be a reference to an array of long values - Creates an instance of an array with 10 long values - will allow valid subscripts in the range of 0-9 Answer - all of the above

Question 46

For the following code, what will be the value of str[2]? String[] str = {"abc", "def", "ghi", "jkl"};

Answer 46

A reference to the string "ghi"

Question 47

Subscript/index numbering always starts at what value?

Answer 47

0

Question 48

Which of the following for loops(to print the size of each string) is valid given the following declaration? String[] names = {"abc", "def", "ghi", "jkl"};

Answer 48

for (int i = 0; i < names.length(); i++ System.out.println(names[i].length);

Question 49

Once an array is created, its size cannot be changed.

Answer 49

True

Question 50

What would be the results of the following code? int[] x = { 55, 33, 88, 22, 99, 11, 44, 66, 77}; int a = 10; if( x[2] > x[5]) a = 5; else a = 8;

Answer 50

a = 5

Question 51

In Java, you do not use the new operator when you use a(n):

Answer 51

Initialization list

Question 52

When an individual element of an array is passed to a method:

Answer 52

The method does not have direct access to the original array.

Question 53

What will be the value of x[8] after the following code has been executed? final int SUB = 12; int[] x = new int[SUB]; int y = 20; for(int i = 0; i < SUB; i++) { x[i] = y; y += 5; }

Answer 53

60

Question 54

When an array of objects is created with new, but not initialized, the array values are set to null.

Answer 54

True (check question)

Question 55

Each array in Java has a public field named ______ that contains the number of elements in an array

Answer 55

length

Question 56

What would be the results of the following code? final int SIZE = 25; int[] array1 = new int[SIZE]; // Code that will put values in array1 int value = 0; for (int a = 0; a < array1.length; a++) { value += array1[a]; }

Answer 56

Value contains the sum of all the values in array1

Question 57

If final int SIZE = 15 and int[] x = new int[SIZE], what would be the range of subscript values that could be used with x[]?

Answer 57

0 through 14

Question 58

To compare the contents of two arrays, you must compare the elements of the two arrays one by one

Answer 58

True

Question 59

What is the value of scores[2][3] in the following array? int [] [] scores = { {88, 80, 79, 92}, {75, 84, 93, 80}, {98, 95, 92, 94}, {91, 84, 88, 96} };

Answer 59

94

Question 60

To return an array of long values from a method, use this as the return type for the method.

Answer 60

long[]

Question 61

Given that String[] str has been initialized, to get a copy of str[0] with all characters converted to upper case, use the following statement:

Answer 61

str[0].toUpperCase();

Question 62

A ragged array is:

Answer 62

a two-dimensional array where the rows are of different lengths

Question 63

What does the following statement do? double[] array1 = new double[10];

Answer 63

- Declares array1 to be a reference to an array of double values - Creates an instance of an array of 10 double values - Will allow subscripts in the range of 0-9 Answer - all of the above

Question 64

What would be the results after the following code is executed? int[] x = {23, 55, 83, 19}; int[] y = {36, 78, 12, 24}; x = y; y = x;

Answer 64

x[] = {36, 78, 12, 24} and y[] = {36, 78, 12, 24}

Question 65

When an array is passed to a method:

Answer 65

- A reference to the array is passed - It is passed just as an object - The method has direct access to the original Answer - all of the above

Question 66

In memory, an array of String objects:

Answer 66

consists of elements, each of which is a reference to a String object

Question 67

What will be returned from the following method? public static float[] getValue(int x)

Answer 67

An array of float values

Question 68

If numbers is a two-dimensional array, which of the following would give the length of row r?

Answer 68

numbers[r].length

Question 69

By default, Java initializes array elements with what value?

Answer 69

0

Question 70

What will be the value of x[1] after the following code is executed? int[] x = {22, 33, 44}; arrayProcess(x[1]); public static void arrayProcess(int a) { a = a + 5; }

Answer 70

33

Question 71

What would be the results after the following code is executed? int[] x = {22, 55, 83, 19}; int[] y = {36, 78, 12, 24}; for (int a = 0; a < x.length; a++) { x[a] = y[a]; y[a] = x[a]; }

Answer 71

x[] = {36, 78, 12, 24} and y[] = {36, 78, 12, 24}

Question 72

An array can hold multiple values of several different types of data simultaneously

Answer 72

False