CH. 3 INTRO TO CLASSES, OBJECTS, METHODS, STRINGS

Question 1

Each class declaration that begins with keyword _____

must be stored in a file that has exactly the same name as the class and ends with the .java file name extension.

Answer 1

public

Question 2

Keyword _____ in a class declaration is followed immediately by the class’s name.

Answer 2

class

Ex: pulbic class Welcome1

Question 3

Keyword ____ requests memory from teh system to store an object, then calls the corresponding class’s constructor to initialize the object

Answer 3

new

Question 4

EACH PARAMETER MUST SPECIFY BOTH

A ____ AND A ____

Answer 4

TYPE AND A NAME

Question 5

BY DEFAULT, CLASSES THAT ARE COMPILED IN THE SAME DIRECTORY ARE CONSIDERED TO BE IN THE SAME PACKAGE, KNOWN AS THE _____

Answer 5

DEFAULT PACKAGE

Question 6

WHEN EACH OBJECT OF A CLASS MAINTAINS ITS OWN COPY OF AN ATTRIBUTE, THE FIELD THAT REPRESENTS THE ATTRIBUTE IS ALSO KNOWN AS A ___________

Answer 6

INSTANCE VARIABLE

Question 7

JAVA PROVIDES TWO PRIMITIVE TYPES FOR STORING FLOATING POINT NUMBERS IN MEMORY:

______ AND _____

Answer 7

FLOAT AND DOUBLE

Question 8

VARIABLES OF TYPE DOUBLE REPRESENT ______

FLOATING POINT NUMBERS

Answer 8

DOUBLE PRECISION

Question 9

SCANNER METHOD ____ RETURNS A DOUBLE VALUE

Answer 9

nextDOUBLE

Question 10

KEYWORD PUBLIC IS AN ACCESS ______.

Answer 10

MODIFIER

Question 11

RETURN TYPE _____ INDICATES THAT A METHOD WILL NOT RETURN A VALUE

Answer 11

VOID

Question 12

SCANNER METHOD _______

READS CHARACTERS UNTIL IT ENCOUNTERS A NEWLINE CHARACTER, THEN RETURNS THOSE CHARACTERS AS A STRING

Answer 12

nextLine

Question 13

CLASS STRING IS IN PACKAGE ______

Answer 13

java.lang

Question 14

A(n) ______ is not required if you always refer to a class with its fully qualified class name.

Answer 14

import declaration

Question 15

A ______ IS A NUMBER WITH A DECIMAL POINT, SUCH AS 7.33, 0.9775 OR 1000.0123

Answer 15

FLOATING POINT NUMBER

Question 16

VARIABLE of type float represent _____ floating point numbers

Answer 16

SINGLE PRECISION

Question 17

The format specifier _____ is used to output values of type float or double

Answer 17

%f

Question 18

Types in Java are divided into two categories

______ types and ______ types

Answer 18

PRIMITIVE AND PARAMETER

Primitive Types: Whole Number Types ( byte, short, int, long) Deciamal Types (float and double)

Question 19

By convention, method names begin with an uppercase first letter, and all subsequent words in the name begin with a capital first letter.

True or False

Answer 19

FALSE

By convention, method names begin with lowercase first letter and all subsequent words in the name begin with a capital first letter

Question 20

An import declaration is not required when one class in a package uses another in the same package

Answer 20

TRUE

Question 21

Empty parentheses following a method name in a method declaration indicate that the method does NOT require any parameters to perform a task

Answer 21

TRUE

Question 22

Variables or methods declared with access modifier “private” are accessible only to methods of the class in which they’re declared

Answer 22

TRUE

Question 23

A primitive-type variable can be used to invoke a method.

Answer 23

FALSE

A primitive-type variable cannot be used to invoke a method - a reference to an object is requried to invoke the objects methods

Question 24

Variable declared in the body of a particular method are known as instance variables and can be used in all methods of the class.

Answer 24

FALSE

Such variables are called “local vairables” and can used only in the method in which they are declared in.

Question 25

Every method’s body is delimited by left and right braces ( { } )

Answer 25

TRUE

Question 26

Primitive-type local variables are initialized by default.

Answer 26

FALSE

Primitive type instance variables are initialized by default

Question 27

Reference-type instance variables are initialized by default to the valule null.

Answer 27

TRUE

Question 28

Any class that contains

 ***public static void*** main ( String [] args )

can be used to execute an application

Answer 28

TRUE

Question 29

The number of arguments in the method call must match the number of parameters in the method declaration’s parameter list.

Answer 29

TRUE

Question 30

Floating-point values that appear in source code are known as floating-point literals and type float by default

Answer 30

FALSE

Such literals are of type double by default

Question 31

What is the difference between local variable and a field

Answer 31

Local variable is declared in the body of a method and can be used only from the point at which it is declared through the end of the method declaration.

A field is declared in a class, but not in the body of any of the class’s methods. Are accessible to all methods of the class.

Question 32

Explain the purpose of a method parameter.

What is the difference between a parameter and an argument?

Answer 32

Parameter represents additional info that a method requries to perform a task, Each parameter rquired by a mehtod is specified in the method’s declaration.

Argument is the actual value for teh method parameter.