Home Page Flashcards Chapter 2 Java Fundamentals - Flashcards

Chapter 2 Java Fundamentals – Flashcards

Patsy Brent

7 July 2022

question

class header

answer

marks the beginning of a class definition

question

class

answer

serves as a container for an application

question

A java program must have at least one class definition.

answer

true

question

access specifier

answer

"public" - unrestricted controls where the class may be accessed from

question

"class"

answer

java key word that indicates the beginning of a class definition

question

"Simple"

answer

the class name.

question

body

answer

everything between the two braces {}

question

method header

answer

marks the beginning of a method

question

method

answer

a group of one or more programming statements that collectively has a name

question

semicolon

answer

marks the end of a statement in Java

question

answer

marks the beginning of a comment

question

( )

answer

used in a method header

question

{ }

answer

encloses a group of statements, such as the contents of a class or a method

question

" "

answer

encloses a string of characters, such as message that is to be printed on the screen

question

;

answer

marks the end of a complete programming statement

question

console output

answer

merely plain text

question

standard output device

answer

refers to the device that displays console output

question

API

answer

Application Programmer Interface; a standard library of prewritten classes for performing specific operations

question

"System" class System.out.println(" ");

answer

part of the Java API. it has member objects and methods for performing system-level operations, such as sending output to the console.

question

"out" object System.out.println(" ");

answer

member of the "System" class. provides methods for sending output to the screen

question

"print" and "println" methods System.out.println(" ");

answer

members of the "out" object. actually perform the work of writing characters on the screen.

question

argument

answer

the value that is to be displayed on the screen is placed inside the parentheses

question

escape sequence

answer

starts with the backslash character (), and is followed by one or more control characters. It allows you to control the way output is displayed by embedding commands within the string itself.

question

answer

newline escape sequence; advances the cursor to the next line for subsequent printing

question

answer

horizontal tab escape sequence; causes the cursor to skip over to the next tab stop

question

answer

backspace escape sequence; causes the cursor to back up, or move left, one position

question

answer

return escape sequence; causes the cursor to go to the beginning of the current line, not the next line

question

answer

single quote escape sequence; causes a single quote mark to be printed

question

answer

double quote escape sequence; causes a double quote mark to be printed

question

variable

answer

a named storage location in the computer's memory

question

literal

answer

a value that is written into the code of a program

question

variable declaration

answer

tells the compiler the variable's name and type of data it will hold Ex.) int value;

question

assignment statement

answer

Ex.) value = 5;

question

string concatenation operator

answer

when the + operator is used with strings; appends one string to another

question

identifier

answer

a programmer-defined name that represents some element of a program; use only alphabetic letters, digits, underscores, or dollar signs

question

key words

answer

make up the core of the java language and each has a specific purpose

question

self-documenting programs

answer

means you get an understanding of what the program is doing just by reading its code

question

Can identifiers begin with a digit?

answer

question

How are variables classified?

answer

according to their data type, which determines the kind of data that may be stored in them.

question

data type

answer

type of data that the variable can hold.

question

primitive data types

answer

data types which cannot be used to create objects

question

floating-point numbers

answer

allow precise measurements, fractional values; ex.) 1.7 -45.316

question

"float" data type

answer

considered a single precision data type; occupies 4 bytes of memory

question

"double" data type

answer

considered a double precision data type; occupies 8 bytes of memory

question

What does it mean to say that Java is a strongly typed language?

answer

it only allows you to store values of compatible data types in variables

question

"char" data type

answer

used to store characters

question

What is the difference between character literals and string literals?

answer

string literals are enclosed in double quote marks, and cannot be assigned to "char" variables. character literals are enclosed in single quote marks.

question

initialization

answer

declaration statement

question

"boolean" data type

answer

allows you to create variables that may hold one of two possible values: "true" or "false"

question

integer division

answer

the operator will perform this when both operands of the division operator are integers

question

truncated

answer

thrown away

question

precedence of arithmetic operators from highest to lowest?

answer

- (unary negation) * / % + -

question

associativity of arithmetic operators

answer

- (unary negation): right to left * / % : left to right + - : left to right

question

What do you need to use to raise a number to a power?

answer

Math.pow method ex.) result = Math.pow(4.0, 2.0); result = 4^2

question

How do you return the square root of a value?

answer

Math.sqrt method Ex.) result = Math.sqrt(9.0); System.out.println(Math.sqrt(25.0)); --> 5.0 is displayed on the screen as output

question

answer

Example: x += 5; x = x + 5;

question

answer

example: y -= 2; y = y - 2;

question

answer

example: z *= 10; z = z * 10;

question

answer

example: a /= b; a = a / b;

question

answer

example: c %= 3; c = c % 3;

question

primitive data type ranking from highest to lowest

answer

double float long int short byte

question

widening conversion

answer

conversion of a value from lower-rank to higher-ranked type

question

narrowing conversion

answer

conversion of a value to lower-ranked type

question

cast operator

answer

lets you manually convert a value, even if it means that a narrowing conversion will take place.

question

named constant

answer

a variable whose value is read only and cannot be changed during the program's execution.

question

instance

answer

each object that is created from a class is called an instance of the class

question

primitive type variables

answer

hold the actual data items with which they are associated

question

class type variable

answer

does not hold the actual data item that is associated with, but holds the memory address of the data item it is associated with.

question

charAt(index)

answer

the argument "index" is an int value and specifies a character position in the string. The first character is at position 0, the second character is at position 1, and so forth. The method returns the character at the specified position. The return value is of the type "char".

question

length( )

answer

this method returns the number of characters in the string. the return value is of the type "int".

question

toLowerCase( )

answer

this method returns a new string that is the lowercase equivalent of the string contained in the calling object.

question

toUpperCase( )

answer

this method returns a new string that is the uppercase equivalent of the string contained in the calling object.

question

scope

answer

the part of the program that has access to the variable; a variable is visible only to statements inside the variable's scope

question

local variables

answer

variables that are declared inside a method

question

comments

answer

notes of explanation that document lines or sections of a program; compiler ignores them; intended for people reading the source code.

question

documentation comment

answer

/** */ typically written just before a class header, giving a brief description of the class or before method header giving a brief description of the method.

question

multi-line comment

answer

/* */ convenient for writing large blocks of comments

question

programming style

answer

refers to the way source code is visually arranged

question

What does import java.util.Scanner; do ?

answer

tells the java compiler where in the java library to find the Scanner class, and makes it available to your program

question

What does JOptionPane do ?

answer

allows you to quickly display a dialog box, which is a small graphical window displaying a message or requesting input.

question

message dialog

answer

a dialog box that displays a message; an OK button is also displayed

question

Input Dialog

answer

a dialog box that prompts the user for input and provides a text field where input is typed; an OK button and Cancel button are also displayed

question

showMessageDialog method

answer

used to display a message dialog

question

import javax.swing.JOptionPane;

answer

tells the compiler where to find the JOptionPane class and makes it available to your program.

question

showInputDialog method

answer

used to display an input dialog

question

System.exit(0);

answer

causes the program to end, and is required if you use the JOptionPane class to display dialog boxes.

question

What happens if the System.exit method is not called?

answer

a thread will continue to execute, even after the end of the main method has been reached

question

Does the System.exit method require an integer argument?

answer

yes

question

Every complete statement ends with a _______: a. period b. parenthesis c. semicolon d. ending brace

answer

c. semicolon

question

The following data 72 'A' "Hello World" 2.8712 are all examples of __________; a. variables b. literals c. strings d. none of these

answer

b. literals

question

a group of statements, such as the contents of a class or a method, are enclosed in _________; a. braces {} b. parentheses () c. brackets [] d. any of these will do

answer

a. braces {}

question

which of thee following are not valid assignment statements? (indicate all that apply); a. total = 9; b. 72 = amount; c. profit = 129 d. letter = 'w';

answer

b. 72 = amount; c. profit = 129

question

which of the following are not valid println statements? (indicate all that apply): a. System.out.println + "Hello World"; b. System.out.println("Have a nice day"); c. out.System.println(value); d. println.out(Programming is great fun);

answer

a. System.out.println + "Hello world"; c. out.System.println(value); d. println.out(programming is great fun);

question

the negation operator is _______; a. unary b. binary c. ternary d. none of these

answer

a. unary

question

This key word is used to declare a named constant. a. constant b. namedConstant c. final d. concrete

answer

c. final

question

These characters mark the beginning of a multi-line comment a. // b./* c.*/ d./**

answer

b. /*

question

these characters mark the beginning of a single-line comment a. // b. /* c. */ d. /**

answer

a.//

question

these characters mark the beginning of a documentation comment a. // b. /* c. */ d. /**

answer

d. /**

question

Which Scanner class method would you use to read a string as an input? a. nextString b. nextLine c. readString d. getLine

answer

b. nextLine

question

which scanner class ethod would you use to read a double as input? a. nextDouble b. getDouble c. readDouble d. none of these; you can't

answer

a. nextDouble

question

You can use this class to display dialog boxes a. JOptionPane b. BufferedReader c. InputStreamReader d. DialogBox

answer

a. JOptionPane

question

When Java converts a lower-ranked value to a higher-ranked type, it is called a(n) __________; a. 4-bit conversion b. escalating conversion c. widening conversion d. narrowing conversion

answer

c. widening conversion

question

this type of operator lets you manually convert a value, even if it means that a narrowing conversion will take place. a. cast b. binary c. uploading d. dot

answer

a. cast

question

true or false: a left brace in a java program is always followed by a right brace later in the program.

answer

true

question

true or false: a variable must be declared before it can be used

answer

true

question

true or false: variable names may begin with a number.

answer

false

question

true or false: you cannot change the value of a variable whose declaration uses the final key word

answer

true

question

true or false: comments that begin with // can be processed by javadoc.

answer

false

question

true or false: if one of an operator's operands is a double, and the other operand is an int, java will automatically convert the value of the double to an int.

answer

false

1 of

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question

class header

answer

marks the beginning of a class definition

question

class

answer

serves as a container for an application

question

A java program must have at least one class definition.

answer

true

question

access specifier

answer

"public" - unrestricted controls where the class may be accessed from

question

"class"

answer

java key word that indicates the beginning of a class definition

question

"Simple"

answer

the class name.

question

body

answer

everything between the two braces {}

question

method header

answer

marks the beginning of a method

question

method

answer

a group of one or more programming statements that collectively has a name

question

semicolon

answer

marks the end of a statement in Java

question

answer

marks the beginning of a comment

question

( )

answer

used in a method header

question

{ }

answer

encloses a group of statements, such as the contents of a class or a method

question

" "

answer

encloses a string of characters, such as message that is to be printed on the screen

question

;

answer

marks the end of a complete programming statement

question

console output

answer

merely plain text

question

standard output device

answer

refers to the device that displays console output

question

API

answer

Application Programmer Interface; a standard library of prewritten classes for performing specific operations

question

"System" class System.out.println(" ");

answer

part of the Java API. it has member objects and methods for performing system-level operations, such as sending output to the console.

question

"out" object System.out.println(" ");

answer

member of the "System" class. provides methods for sending output to the screen

question

"print" and "println" methods System.out.println(" ");

answer

members of the "out" object. actually perform the work of writing characters on the screen.

question

argument

answer

the value that is to be displayed on the screen is placed inside the parentheses

question

escape sequence

answer

starts with the backslash character (), and is followed by one or more control characters. It allows you to control the way output is displayed by embedding commands within the string itself.

question

answer

newline escape sequence; advances the cursor to the next line for subsequent printing

question

answer

horizontal tab escape sequence; causes the cursor to skip over to the next tab stop

question

answer

backspace escape sequence; causes the cursor to back up, or move left, one position

question

answer

return escape sequence; causes the cursor to go to the beginning of the current line, not the next line

question

answer

single quote escape sequence; causes a single quote mark to be printed

question

answer

double quote escape sequence; causes a double quote mark to be printed

question

variable

answer

a named storage location in the computer's memory

question

literal

answer

a value that is written into the code of a program

question

variable declaration

answer

tells the compiler the variable's name and type of data it will hold Ex.) int value;

question

assignment statement

answer

Ex.) value = 5;

question

string concatenation operator

answer

when the + operator is used with strings; appends one string to another

question

identifier

answer

a programmer-defined name that represents some element of a program; use only alphabetic letters, digits, underscores, or dollar signs

question

key words

answer

make up the core of the java language and each has a specific purpose

question

self-documenting programs

answer

means you get an understanding of what the program is doing just by reading its code

question

Can identifiers begin with a digit?

answer

question

How are variables classified?

answer

according to their data type, which determines the kind of data that may be stored in them.

question

data type

answer

type of data that the variable can hold.

question

primitive data types

answer

data types which cannot be used to create objects

question

floating-point numbers

answer

allow precise measurements, fractional values; ex.) 1.7 -45.316

question

"float" data type

answer

considered a single precision data type; occupies 4 bytes of memory

question

"double" data type

answer

considered a double precision data type; occupies 8 bytes of memory

question

What does it mean to say that Java is a strongly typed language?

answer

it only allows you to store values of compatible data types in variables

question

"char" data type

answer

used to store characters

question

What is the difference between character literals and string literals?

answer

string literals are enclosed in double quote marks, and cannot be assigned to "char" variables. character literals are enclosed in single quote marks.

question

initialization

answer

declaration statement

question

"boolean" data type

answer

allows you to create variables that may hold one of two possible values: "true" or "false"

question

integer division

answer

the operator will perform this when both operands of the division operator are integers

question

truncated

answer

thrown away

question

precedence of arithmetic operators from highest to lowest?

answer

- (unary negation) * / % + -

question

associativity of arithmetic operators

answer

- (unary negation): right to left * / % : left to right + - : left to right

question

What do you need to use to raise a number to a power?

answer

Math.pow method ex.) result = Math.pow(4.0, 2.0); result = 4^2

question

How do you return the square root of a value?

answer

Math.sqrt method Ex.) result = Math.sqrt(9.0); System.out.println(Math.sqrt(25.0)); --> 5.0 is displayed on the screen as output

question

answer

Example: x += 5; x = x + 5;

question

answer

example: y -= 2; y = y - 2;

question

answer

example: z *= 10; z = z * 10;

question

answer

example: a /= b; a = a / b;

question

answer

example: c %= 3; c = c % 3;

question

primitive data type ranking from highest to lowest

answer

double float long int short byte

question

widening conversion

answer

conversion of a value from lower-rank to higher-ranked type

question

narrowing conversion

answer

conversion of a value to lower-ranked type

question

cast operator

answer

lets you manually convert a value, even if it means that a narrowing conversion will take place.

question

named constant

answer

a variable whose value is read only and cannot be changed during the program's execution.

question

instance

answer

each object that is created from a class is called an instance of the class

question

primitive type variables

answer

hold the actual data items with which they are associated

question

class type variable

answer

does not hold the actual data item that is associated with, but holds the memory address of the data item it is associated with.

question

charAt(index)

answer

question

length( )

answer

this method returns the number of characters in the string. the return value is of the type "int".

question

toLowerCase( )

answer

this method returns a new string that is the lowercase equivalent of the string contained in the calling object.

question

toUpperCase( )

answer

this method returns a new string that is the uppercase equivalent of the string contained in the calling object.

question

scope

answer

the part of the program that has access to the variable; a variable is visible only to statements inside the variable's scope

question

local variables

answer

variables that are declared inside a method

question

comments

answer

notes of explanation that document lines or sections of a program; compiler ignores them; intended for people reading the source code.

question

documentation comment

answer

/** */ typically written just before a class header, giving a brief description of the class or before method header giving a brief description of the method.

question

multi-line comment

answer

/* */ convenient for writing large blocks of comments

question

programming style

answer

refers to the way source code is visually arranged

question

What does import java.util.Scanner; do ?

answer

tells the java compiler where in the java library to find the Scanner class, and makes it available to your program

question

What does JOptionPane do ?

answer

allows you to quickly display a dialog box, which is a small graphical window displaying a message or requesting input.

question

message dialog

answer

a dialog box that displays a message; an OK button is also displayed

question

Input Dialog

answer

a dialog box that prompts the user for input and provides a text field where input is typed; an OK button and Cancel button are also displayed

question

showMessageDialog method

answer

used to display a message dialog

question

import javax.swing.JOptionPane;

answer

tells the compiler where to find the JOptionPane class and makes it available to your program.

question

showInputDialog method

answer

used to display an input dialog

question

System.exit(0);

answer

causes the program to end, and is required if you use the JOptionPane class to display dialog boxes.

question

What happens if the System.exit method is not called?

answer

a thread will continue to execute, even after the end of the main method has been reached

question

Does the System.exit method require an integer argument?

answer

yes

question

Every complete statement ends with a _______: a. period b. parenthesis c. semicolon d. ending brace

answer

c. semicolon

question

The following data 72 'A' "Hello World" 2.8712 are all examples of __________; a. variables b. literals c. strings d. none of these

answer

b. literals

question

a group of statements, such as the contents of a class or a method, are enclosed in _________; a. braces {} b. parentheses () c. brackets [] d. any of these will do

answer

a. braces {}

question

which of thee following are not valid assignment statements? (indicate all that apply); a. total = 9; b. 72 = amount; c. profit = 129 d. letter = 'w';

answer

b. 72 = amount; c. profit = 129

question

answer

a. System.out.println + "Hello world"; c. out.System.println(value); d. println.out(programming is great fun);

question

the negation operator is _______; a. unary b. binary c. ternary d. none of these

answer

a. unary

question

This key word is used to declare a named constant. a. constant b. namedConstant c. final d. concrete

answer

c. final

question

These characters mark the beginning of a multi-line comment a. // b./* c.*/ d./**

answer

b. /*

question

these characters mark the beginning of a single-line comment a. // b. /* c. */ d. /**

answer

a.//

question

these characters mark the beginning of a documentation comment a. // b. /* c. */ d. /**

answer

d. /**

question

Which Scanner class method would you use to read a string as an input? a. nextString b. nextLine c. readString d. getLine

answer

b. nextLine

question

which scanner class ethod would you use to read a double as input? a. nextDouble b. getDouble c. readDouble d. none of these; you can't

answer

a. nextDouble

question

You can use this class to display dialog boxes a. JOptionPane b. BufferedReader c. InputStreamReader d. DialogBox

answer

a. JOptionPane

question

When Java converts a lower-ranked value to a higher-ranked type, it is called a(n) __________; a. 4-bit conversion b. escalating conversion c. widening conversion d. narrowing conversion

answer

c. widening conversion

question

this type of operator lets you manually convert a value, even if it means that a narrowing conversion will take place. a. cast b. binary c. uploading d. dot

answer

a. cast

question

true or false: a left brace in a java program is always followed by a right brace later in the program.

answer

true

question

true or false: a variable must be declared before it can be used

answer

true

question

true or false: variable names may begin with a number.

answer

false

question

true or false: you cannot change the value of a variable whose declaration uses the final key word

answer

true

question

true or false: comments that begin with // can be processed by javadoc.

answer

false

question

true or false: if one of an operator's operands is a double, and the other operand is an int, java will automatically convert the value of the double to an int.

answer

false

Chapter 2 Java Fundamentals – Flashcards

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