Moment 4

Question 1

Arrays (p. 246) are?

Answer 1

fixed-length data structures consisting of related data items of the same type.

Question 2

Types in Java are divided into two categories, which?

Answer 2

—primitive types and reference types.

Question 3

The primitive types are?

Answer 3

boolean, byte, char, short, int, long, float and double.

All other types are reference types, so classes, which specify the types of objects, are reference types.

Question 4

A primitive-type variable can store?

Answer 4

exactly one value of its declared type at a time.

Question 5

Reference-type variables (called references; p. 247) store the?

Answer 5

location of an object in the computer’s memory. Such variables refer to objects in the program.

Question 6

A reference to an object (p. 247) is required to invoke an?

Answer 6

object’s methods. A primitive-type variable does not refer to an object and therefore cannot be used to invoke a method.

Question 7

An array is a group of variables (called elements or components; p. 247) containing values that?

Answer 7

all have the same type. Arrays are objects, so they’re considered reference types.

Question 8

A program refers to any one of an array’s elements with an array-access expression (p. 248) that includes?

Answer 8

the name of the array followed by the index of the particular element in square brackets ([]; p. 248).

Question 9

The first element in every array has index?

Answer 9

zero (p. 248) and is sometimes called the zeroth element.

Question 10

An index must be a nonnegative?

Answer 10

integer. A program can use an expression as an index.

Question 11

An array object knows its own length and stores this information in a?

Answer 11

“length” instance variable

Question 12

To create an array object, specify the array’s?

Answer 12

element type and the number of elements as part of an array-creation expression (p. 249) that uses keyword new.

Question 13

When an array is created, each element receives a default value, which?

Answer 13

zero for numeric primitive-type elements, false for boolean elements and null for references.

Question 14

In an array declaration, the type and the square brackets can be combined at the beginning of the declaration to indicate that?

Answer 14

all the identifiers in the declaration are array variables.

Question 15

Every element of a primitive-type array contains a?

Answer 15

variable of the array’s declared type.

Question 16

Every element of a reference-type array is a reference to an?

Answer 16

object of the array’s declared type.

Question 17

A program can create an array and initialize its elements with an?

Answer 17

array initializer (p. 251).

Question 18

Constant variables (p. 253) are declared with keyword?

Answer 18

final, must be initialized before they’re used and cannot be modified thereafter.

Question 19

An exception indicates a?

Answer 19

problem that occurs while a program executes.

Question 20

Exception handling (p. 259) enables you to?

Answer 20

create fault-tolerant programs.

Question 21

When a Java program executes, the JVM checks array indices to ensure that?

Answer 21

they’re greater than or equal to 0 and less than the array’s length.

Question 22

If a program uses an invalid array index, Java generates an?

Answer 22

exception (p. 259) to indicate that an error occurred in the program at execution time.

Question 23

To handle an exception, place any code that might throw an exception (p. 259) in a?

Answer 23

“try” statement.

Question 24

The “try” block (p. 259) contains the code that might throw an exception, and the “catch” block (p. 259) contains the

Answer 24

code that handles the exception if one occurs.

Question 25

You can have many “catch” blocks to handle?

Answer 25

different types of exceptions that might be thrown in the corresponding “try” block.

Question 26

When a “try” block terminates, any variables declared in the “try” block go?

Answer 26

out of scope.

Question 27

A “catch” block declares a

Answer 27

type and an exception parameter. Inside the “catch” block, you can use the parameter’s identifier to interact with a caught exception object.

Question 28

When a program is executed, array element indices are?

Answer 28

checked for validity

Question 29

all array element indices must be greater than or equal?

Answer 29

to 0 and less than the length of the array.

Question 30

If an attempt is made to use an invalid index to access an element, an?

Answer 30

“ArrayIndexOutOfBoundsException” (p. 259) exception occurs.

Question 31

An exception object’s “toString” method returns the?

Answer 31

exception’s error message.

Question 32

The enhanced for statement (p. 260) allows you to?

Answer 32

iterate through the elements of an array or a collection without using a counter.

Question 33

The syntax of an enhanced “for” statement is:?

Answer 33

for (Type parameter : arrayName)
{
statement
}

Question 34

The enhanced for statement cannot be used to

Answer 34

modify elements in an array.

Question 35

If a program needs to modify elements, use the?

Answer 35

traditional counter-controlled for statement.

Question 36

When an argument is passed by value, a copy of the argument’s value is made and passed to?

Answer 36

the called method. The called method works exclusively with the copy.

Question 37

When an argument is passed by reference (p. 264), the called method can access the?

Answer 37

argument’s value in the caller directly and possibly modify it.

Question 38

All arguments in Java are passed by?

Answer 38

value.

Question 39

A method call can pass two types of values to a method, which?

Answer 39

copies of primitive values and copies of references to objects. Although an object’s reference is passed by value (p. 264), a method can still interact with the referenced object by calling its public methods using the copy of the object’s reference.

Question 40

When you pass an array or an individual array element of a reference type to a method, the called method receives a?

Answer 40

copy of the array or element’s reference.

When you pass an individual element of a primitive type, the called method receives a copy of the element’s value.

Question 41

To pass an individual array element to a method, use the?

Answer 41

indexed name of the array.

Question 42

Multidimensional arrays with two dimensions are often used to?

Answer 42

represent tables of values consisting of information arranged in rows and columns.

Question 43

two-dimensional array (p. 264) with m rows and n columns is called an?

Answer 43

m-by-n array.

Question 44

An m-by-n array can be initialized with an array initializer of the form?

Answer 44

arrayType[][] arrayName = {{row1 initializer}, {row2 initializer}, …};

Question 45

Multidimensional arrays are maintained as arrays of?

Answer 45

separate one-dimensional arrays. As a result, the lengths of the rows in a two-dimensional array are not required to be the same.

Question 46

A multidimensional array with the same number of columns in every row can be created with an?

Answer 46

array-creation expression of the form

arrayType[][] arrayName = new arrayType[numRows][numColumns];

Question 47

An argument type followed by an ellipsis (…; p. 268) in a method’s parameter list indicates that?

Answer 47

the method receives a variable number of arguments of that particular type.

Question 48

The ellipsis can occur?

Answer 48

only once in a method’s parameter list. It must be at the end of the parameter list.

Question 49

A variable-length argument list (p. 268) is treated as?

Answer 49

an array within the method body. The number of arguments in the array can be obtained using the array’s length field.

Question 50

Passing arguments to main (p. 269) from the command line is achieved by?

Answer 50

including a parameter of type String[] in the parameter list of main. By convention, main’s parameter is named args.

Question 51

Java passes command-line arguments that appear after the class name in the java command to the application’s “main” method as?

Answer 51

“Strings” in the array args.

Question 52

Lists and tables of values can be stored in ____________ and _______________ .

Answer 52

arrays, collections.

Question 53

An array is a group of _______________ (called elements or components) containing values that all have the same ______________.

Answer 53

variables, type.

Question 54

The _____________ allows you to iterate through an array’s elements without using a
counter.

Answer 54

enhanced “for” statement.

Question 55

The number used to refer to a particular array element is called the element’s _____________.

Answer 55

index (or subscript or position number).

Question 56

An array that uses two indices is referred to as a(n) ___________ array.

Answer 56

two-dimensional.

Question 57

Use the enhanced for statement _______________ to walk through “double” array numbers.

Answer 57

for (double d : numbers).

Question 58

Command-line arguments are stored in _____________.

Answer 58

an array of “Strings”, called “args” by convention.

Question 59

Use the expression _____________ to receive the total number of arguments in a command line. Assume that command-line arguments are stored in String[] args.

Answer 59

args.length.

Question 60

Given the command java MyClass test, the first command-line argument is _______________.

Answer 60

test.

Question 61

A(n) __________ in the parameter list of a method indicates that the method can receive a variable number of arguments.

Answer 61

ellipsis (…).