Final- Java Chap 2 Gaddis

Question 1

A Java source code file contains one or more Java…

Answer 1

classes

Question 2

Rule: If more than one class is in a source code file…

Answer 2

only one of them may be public

Question 3

The public class and the filename of the source code file…

Answer 3

must match

Question 4

Each Java class can be separated into…

Answer 4

parts

Question 5

to compile vs to run

Answer 5

to compile:
javac Simple.java

to run:
java Simple

Question 6

curly braces

Answer 6

contain all of the data and methods for a class. They open on the line after the class header

Question 7

after the class header and the opening curly bracket, there is a…

Answer 7

method header and an opening curly bracket for the method

Question 8

method headers look like this:

Answer 8

public statis void main (String[] args)

{

Question 9

The application begins

Answer 9

after the method header

Question 10

Between the curly brackets of the method are…

Answer 10

all the actions to be completed during said method

Question 11

Java statement that is executed when the program runs

Answer 11

is indented and within the curly brackets of the method.

ex: System.out.println(“Programming rocks!”);

Question 12

Ignored by compilers

Answer 12

comments

Question 13

the class header communicates that

Answer 13

other classes can use it (public), that it is a java class (class), and the name (Simple)

Question 14

curly braces

Answer 14

define the scope of a class or method

Question 15

In this method:
public static void main(String[] args)

args is…

Answer 15

a variable name that can be programmer defined

Question 16

The method

Answer 16

is the line of code that the java command will run first. It starts the program

Question 17

Every Java application must have a

Answer 17

main method

Question 18

When the program runs, the statements within the main method will be

Answer 18

executed

Question 19

Semi-colons only end lines that…

Answer 19

are java statements. Not comments or java framework like class headers or method headers

Question 20

A .java file may contain many classes but may only have…

Answer 20

one public class

Question 21

If a .java file has a public class, the class must have…

Answer 21

the same name as the file.

Question 22

//

Answer 22

marks the beginning of a single line comment. Anything after the // on the line will be ignored by the compiler

Question 23

( )

Answer 23

used in a method header to mark the parameter list

Question 24

{ }

Answer 24

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

Question 25

” “

Answer 25

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

Question 26

;

Answer 26

marks the end of a complete programming statement

Question 27

standard output device

Answer 27

the console window that starts a java application

Question 28

standard input device

Answer 28

the keyboard

Question 29

Java sends info to the standard output device by using

Answer 29

a Java class stored in the standard Java library

Question 30

Java classes in the standard Java library are accessed using the

Answer 30

Java Applications Programming Interface (API)

Question 31

The standard Java library is commonly referred to as

Answer 31

the Java API

Question 32

System.out.println(“Programming is great fun!”);

is an example of…

Answer 32

a programming statement

Question 33

in the programming statement:
System.out.println(“Programming is great fun!”);

System is…

Answer 33

a class called upon by the program that contains methods and objects that perform system level tasks

Question 34

In the programming statement:
System.out.println(“Programming is great fun!”);

out is

Answer 34

an object, which is a member of the System class and contains the methods print and println

Question 35

print and println methods actually perform the task of…

Answer 35

sending characters to the output device

Question 36

The println method automatically…

Answer 36

places a newline character at the end of whatever is being printed out

Question 37

Would the following lines be printed on the same or separate lines? Why?

System.out.println(“This is being printed out”);
System.out.println(“on two separate lines.”);

Answer 37

Separate lines since the first statement has println which sens a newline command to the screen.

Question 38

The print statement does not

Answer 38

put a newline character at the end of the output.

Question 39

System.out.print(“These lines will be”);
System.out.print(“printed on”);
System.out.println(“the same line.”);

Answer 39

Because they didnt use println

Question 40

\n

Answer 40

newline character. A special character or escape sequence that can be put into the output to start a new line in the print statement.

Question 41

escape sequences

Answer 41

allow the programmer to print characters that otherwise would be unprintable

Question 42

\n

Answer 42

Escape sequence. newline. Advances the cursor to the next line for subsequent printing

Question 43

\t

Answer 43

Escape sequence. Tab. Causes the cursor to skip over to the next tab stop

Question 44

\b

Answer 44

Escape sequence. backspace. Causes the cursor to back up (move left) one position.

Question 45

\r

Answer 45

Escape sequence. Carriage return. Causes the cursor to go to the beginning of the current line, not the next line.

Question 46

\

Answer 46

Escape sequence. Backslash. Causes a backslash to be printed.

Question 47

'

Answer 47

Escape sequence, Single quote. Causes a single quote to be printed

Question 48

"

Answer 48

Escape sequence. Double quote.

Question 49

Even though the escape sequences have 2 characters, they are treated by the compiler…

Answer 49

as a single character.

Question 50

What output would result from this?:
System.out.print(“These are our top sellers:\n”);
System.out.print(“\tComputer games\n\tCoffee\n “);
System.out.println(“\tAspirin”);

Answer 50

These are our top sellers:
Computer games
Coffee
Asprin

Question 51

Complex text output can be achieved with

Answer 51

escape sequences.

Question 52

the + operator can be used as:

Answer 52

a concatenation operator and an addition operator

Question 53

If either side of the + operator is a string, the result will be a…

Answer 53

string.

Question 54

string literals

Answer 54

inside (“ “) to be printed as part of a programming statement. Must be treated with care.

Question 55

A string literal cannot

Answer 55

span lines in a Java source code file.
Example:
System.out.println(“This line is too long and now it has spanned more than one line, which will cause a syntax error to be generated by the compiler. “);

Question 56

What can fix the problem created by the fact that string literals cannot span more than one line?

Answer 56

The string concatenation operator.
Example:
System.out.println(“These lines are “ +
“now ok and will not “ +
“cause the error as before.”);

Question 57

Can string concatenation join various data types?

Answer 57

Yes.

Question 58

If an addition operation is needed in a print statement

Answer 58

it must be put into parenthesis.
Example:
“\n\tSecond = “ + (6 + 4) + “,”

Question 59

There are 3 methods for commenting codes

Answer 59

The first is //

Question 60

/…/

Answer 60

block comment. Everything beginning with /* and ending with the first */ will be ignored by the compiler. This comment type cannot be nested.

Question 61

/**…*/

Answer 61

Javadoc comment. This is a special version of the previous block comment that allows comments to be documented by the javadoc utility program. Also cannot be nested.

Question 62

Although java has a strict syntax, what characters are ignored by the compiler?

Answer 62

whitespace

Question 63

Java whitespace characters (5):

Answer 63

space, tab, newline, carriage return, form feed

Question 64

Each block of code should be…

Answer 64

indented a few spaces from its surrounding block. 2-4 spaces are sufficient

Question 65

Why should tab characters be avoided?

Answer 65

tabs can vary in size between applications and devices.