Object-Oriented Programming

Question 1

content

Answer 1

• classes and interfaces
• objects with attributes and methods

Question 2

object

Answer 2

functional unit

Question 3

Advantages of OO Programming

Answer 3

• improved software-development productivity
• improved software maintainability
• faster development
• lower cost of development
• higher-quality software

Question 4

Disadvantages of OO Programming

Answer 4

• steep learning curve
• larger program size
• slower programs
• not suitable for all kinds of programs

Question 5

instantiate an object

Answer 5

e.g.

Bicycle bike1 = new Bicycle();

Question 6

class definition

Answer 6

• data fields (attributes)
• constructor
• methods

Question 7

Inheritance

Answer 7

• reuse of existing classes when creating a new class
• derived class will inherit public operations defined in the base class

Question 8

child class

Answer 8

• inherit public operations of parent class
• may override certain attributes or methods
• only specefies what is different to parent class

Question 9

Access Control Attribute Keywords

Answer 9

private -> protected -> no modifier -> public

Question 10

Encapsulation

Answer 10

• put data and operations on this data private
• user does not need to know the implementation details
• ability to access and modify the data through public operations -> setters and getters

Question 11

Polymorphism

Answer 11

• different objects respond to the same message in different ways
• 1 method with different implementations
• often in subclasses

Question 12

Interface

Answer 12

• combination of all public methods and properties of an object
• set of specifications you can always count on - a “contract”

Question 13

Definining and Implementing Interfaces

Answer 13

• can’t be instantiated
• no constructors
• all methods are abstract
• cannot contain instance fields
• contains only both static and final declared fields
• not extended by a class, but implemented by a class.
• can extend multiple interfaces