Unit 3: Methods/Functions Continued

Question 1

An Object is a combination of _____ and ______

Answer 1

Data, procedures

Question 2

Data in an object are known as…

Answer 2

attributes, fields, data members, or instance variables. An object stores data in its fields

Question 3

Procedures in an object are known as…

Answer 3

Methods, member-functions, member-methods, or method-members

Question 4

The first step in creating an object is to outline and define the characteristics of that object, with the aid of a _______

Answer 4

Class

Question 5

Define: Class

Answer 5

A program structure that allows a programmer to define the characteristics of an object that needs to be created

Question 6

A class may contain ______ only or ________ only

Answer 6

Methods, attributes

Question 7

What does object oriented programming (OOP) do?

Answer 7

Allows creating ‘objects’ and makes a program a cluster of interacting objects

Question 8

Why the object-oriented approach?

Answer 8

Appropriate for programs that model the real world, accelerate system development, simplify systems integration and standardization, suitable for building huge applications

Question 9

True or False: class is a keyword

Answer 9

True

Question 10

Define: Access modifier

Answer 10

A Java keyword that indicates how a field, method, or class can be accessed in a program

Question 11

What are the three Java access modifiers:

Answer 11

Protected, public, private

Question 12

If there is no access modifier used, it is considered to have a _____ modifier

Answer 12

Default

Question 13

Define: public (access modifier)

Answer 13

Accessible from any class or package in the Java program

Question 14

Define: private (access modifier)

Answer 14

Accessible only within the class-definition. Outside a class, the private data-members and methods of that class can be accessed indirectly by the public methods of the same class via its objects

Question 15

Define: protected (access modifier)

Answer 15

Allows for the data-members, methods, and constructors accessible in the same package and subclasses

Question 16

Define: Default (access modifier)

Answer 16

Access from the same class and same package only

Question 17

Classes that need to be used by other classes are typically made __________

Answer 17

Public

Question 18

Access modifier for any outer-class can be _____. Only inner-class can have ______ access modifier

Answer 18

Public, private

Question 19

True or False: In Java, an object is a reference-variable of a defined class type, also referred to as an instance of a class

Answer 19

True

Question 20

Since an object is an instance of a class, the non-static data-members/fields are also known as ________, while the non-static methods/function-members are known as ________

Answer 20

Instance variables, instance methods

Question 21

Demonstrate the syntax of object declaration in Java

Answer 21

ClassName referenceVariableName;

Question 22

True or False: An object reference-variable can be used before initialization

Answer 22

False

Question 23

Define: Encapslation

Answer 23

Enclosing the proper attributes and methods inside a single class

Question 24

What does encapsulation accomplish?

Answer 24

Ensures data-hiding and ensures the class is self-contained

Question 25

Define: Getter methods (accessor methods)

Answer 25

The methods that retrieve/get the data-values of the field

Question 26

Define: Setter methods (mutator methods)

Answer 26

The methods that modify the data-values of the field

Question 27

True or False: Getter and setter methods must be public

Answer 27

True

Question 28

By convention, the names of Getter and Setter methods use the prefix ____ and _____ followed by the _____

Answer 28

get, set, field-name (Example: getLength, setLength, getWidth, setWidth)

Question 29

The objects in a program are initialized using a special method, called __________

Answer 29

constructor

Question 30

True or False: The initialization of a method is done inside the definition of the constructor

Answer 30

True

Question 31

Describe the properties of a constructor

Answer 31

Typically a public member method (can be private in a special scenario), must have the same name as the class, do not have a return type (not even void), can be overloaded

Question 32

True or False: A constructor is automatically called when an object is constructed in the heap with the initialized values assigned to its members with the aid of a reference variable using the new operator

Answer 32

True

Question 33

True or False: The String object is so widely used that this code can be simplified to the shorthand listed below: String name = new String("Bob Marley"); String name = "Bob Marley");

Answer 33

True

Question 34

If name is a data-field in the following java statement, what does the name contain: String name;

Answer 34

null

Question 35

If name is a reference-variable inside the main() method in the following java statement, what does name contain: String name;

Answer 35

Nothing, because it has not been initialized

Question 36

True or False: A constructor is a special member method which is called every time an object is created and is designed to initialize member variables

Answer 36

True

Question 37

True or False: There can be more than one constructor in a given class

Answer 37

True

Question 38

If Circle is a class name in Java, what does the following statement inside a method do: Circle myCircle;

Answer 38

Nothing, because it has not been initialized

Question 39

True or False: Public methods in a class can access private members of the objects of the same class

Answer 39

True

Question 40

True or False: Private member methods of a class can access private members of other classes

Answer 40

False

Question 41

What should the visibility standard of data members in a class?

Answer 41

They can have no visibility modifier (default) or they can be private or public or protected

Question 42

If a class in Java does not contain any visibility modifier (such as private, public, protected) can that class be used by any other class from the other packages?

Answer 42

No

Question 43

True or False: When passing a primitive-type parameter to a method, the parameter is copied to a new variable

Answer 43

True

Question 44

True or False: When passing a primitive-type parameter to a method, changes to this parameter inside the called method affects the original value in the calling method

Answer 44

False

Question 45

True or False: When passing a reference-variable, referring to an object, during a method-call, changes to this object inside the called method affects the original object in the calling method

Answer 45

True

Question 46

The ________ operator can be used to assign one reference-variable of an object to another

Answer 46

Assignment (=)

Question 47

True or False: When you design a class, you decide on the name of the class

Answer 47

True

Question 48

True or False: When you use a class, you decide on the names of the instances (i.e., the reference-variable of an object) of that class

Answer 48

True

Question 49

What is the default value of the boolean type local variable in Java?

Answer 49

Java assigns no default value to a local variable