Chapter 6

Question 1

True or False, Constructors create and initialize new objects?

Answer 1

True

Question 2

True or False, A constructor is a special method that is called when you use the new operator to create a new object

Answer 2

True

Question 3

Using __ calls a constructor

Answer 3

new

Question 4

What part is earthSpecies and what part is Species  in 
Species earthSpecies = new Species();

Answer 4

• earthSpecies to be a name for an object
• in class Species.
• The second part, newSpecies(), creates and initializes a new object, whose address is then assigned to earthSpecies.
• Species() is a call to the constructor that Java provided for the class. The parentheses are empty because this particular constructor takes no arguments.

Question 5

True/False .A constructor supplied by Java uses default initial values

Answer 5

True

Question 6

True or False, the constructors create objects and give their instance variables default initial values. These values might not be what you want, however. Instead, you may wish to have some or all instance variables initialized to your specifications at the time an object is created. You can do this by writing your own constructors.

Answer 6

True

Question 7

Constructors serve essentially the same purpose as ___

Answer 7

setters or set methods

Question 8

True or False, A constructor can perform any action you write into its definition, but a constructor is meant to perform initializing actions, such as initializing the values of instance variables.

Answer 8

True

Question 9

True or False, When you define a constructor, you do not specify any return type, not even void. These constructors look very much like our set methods, which are void methods.

Answer 9

True

Question 10

Instance variables that you do not initialize are given ___ initial values by Java

Answer 10

default

Question 11

True or False, A default constructor has no parameters

Answer 11

True

Question 12

When you create a new object by using the operator new, you must always include a __ to a constructor.

Answer 12

call

Question 13

Pet fish = new Pet(“Wanda”, 2, 0.25); , describe this line of code

Answer 13

The part Pet(“Wanda”, 2, 0.25) is a call to the constructor in Pet that takes three arguments:
This statement creates a new object to represent a pet named Wanda who is 2 years old and weighs 0.25 pound.

Question 14

True of False, You cannot use an existing object to call a constructor

Answer 14

True

Question 15

True of False, A constructor that calls a public method can cause a problem

Answer 15

True

Question 16

A constructor and a __ method can call the same private method

Answer 16

set

Question 17

What is “ this “ called? this(initialName, 0, 0);

Answer 17

Calling a Constructor from Other Constructors

Question 18

___ variables and ___ methods belong to a class as a whole and not to an individual object.

Answer 18

Static, Static

Question 19

There are three types of variables

Answer 19

local variables, instance variables, and static (class) variables.

Question 20

Invoke a __ method using the class name, not an object name

Answer 20

static

Question 21

True or False, A non-static method can reference a static variable or call a static method

Answer 21

True

Question 22

True or False ,A static method cannot call a non-static method unless it has an object

Answer 22

True

Question 23

could a static method reference an instance variable?

Answer 23

no

Question 24

A static method can call only a __ method

Answer 24

static

Question 25

True or false, a static method can invoke only static methods and reference only static variables. It cannot invoke a non-static method of the same class unless you have an object of the class to use in the invocation.

Answer 25

True

Question 26

it makes sense to have a main method within a class definition. The class can then be used for two purposes: It can be used to create objects in other classes, or it can be ____ .

Answer 26

run as a program

Question 27

What do you call the need to convert the primitive value—such as the int value 42—to an “equivalent” value of some class type that corresponds to the primitive type int?

Answer 27

wrapper class

Question 28

The constant value___ is a special predefined constant that you can use to give a value to any variable of any class type.

Answer 28

null

Question 29

What is driver program?

Answer 29

All they have to do is give the method some arguments and invoke the method.

Question 30

When you give two or more methods the same name within the same class, you are____ the method name.

Answer 30

Overloading

Question 31

A ____ is a collection of classes

Answer 31

package

Question 32

A ___ is simply a collection of classes that have been grouped together into a folder. The name of the folder is the name of the _____ .

Answer 32

package, package

Question 33

You can use all the classes that are in a package within any program or class definition by placing ____ statement that names the package at the start of the file containing the program or class definition.

Answer 33

an import …

syntax: import Package_Name.Class_Name

Question 34

To import all the classes in the package general.utilities, you would use the following import statement:

Answer 34

import general.utilities.*;

Question 35

The value of your class __ variable tells Java where to begin its search for a package,

Answer 35

path