Crying for Midterm 1

Question 1

The Metaphor of the Object_Oriented Paradigm

Answer 1

Everything is an object
A class is a collection of objects

Question 2

Implementor, Client, Designer

Answer 2

Implementor: Formulates the algorithms
Client: instantiates objects and uses methods
Designer: defines abstractions and chooses interfaces

Question 3

Abstraction

Answer 3

Polymorphism; specifically how it can relate to inheritance and such

Question 4

Composition

Answer 4

The idea of objects attributes being other objects

Question 5

Attributes, Methods, and Constructors

Answer 5

Attributes: data stored inside of an object
Methods: Behaviors stored inside of objects/classes used to instantiate the objects
Constructors: only available in Classes, used to instantiate objects themselves (making sure they are stable)
Encapsulation is a common theme with attributes and methods

Question 6

Definitions of an “interface”

Answer 6

1. GUI that we all know and love
2. Java keyword interface
3. The interactions between Objects and Classes and their respective interfaces
4. The Java API

Question 7

Packages

Answer 7

A storage system used to group together different classes into different positions on a computer.
Classes within the same package can use protected variables
Allows two classes to have the same name but different locations, making “overloading” names possible

Question 8

Design: object responsibilities

Answer 8

An objects responsibility is to be stable, have a relatively discrete interface, and to do it’s job and only it’s job.
Objects should have private attributes exclusively.
Objects should have attributes to display necessary information within the general interface.

Question 9

Abstract classes

Answer 9

CANNOT have constructors
used as a midway between classes and interfaces
can have instance variables
single inheritance
can be made up of abstract methods and normal methods

Question 10

Abstract methods

Answer 10

methods that consist of only a return type, name, and parameters
Need to be overloaded in child classes w/ methods

Question 11

Classes

Answer 11

a blueprint for objects
used to define everything that specific object would and could ever need
must have a constructor (if not given one the Java JVM makes one anyways)

Question 12

Interfaces

Answer 12

CANNOT have a constructor
CANNOT have instance variables
CAN have constant variables
supports multiple implementations
All implementing classes must include all methods present within the interface
All interface methods MUST be abstract

Question 13

Polymorphism

Answer 13

The act of overriding methods in child classes to make them more personal for each specific object
Insanely powerful
When you call a method, you will get specifically the most specific instance of that method if it applies to the object in question

Question 14

Exceptions

Answer 14

The act of managing things that go wrong in code.

Question 15

Unchecked exceptions

Answer 15

Exceptions caused by errors present within the implementation that can be fixed by better coding logic

Question 16

Checked Exceptions

Answer 16

Exceptions caused by things that go wrong during runtime (I/O errors, FileNotFoundExceptions, etc)

Question 17

throws keyword

Answer 17

Belongs in method signature
used on all methods that throw an exception.
NOT used in try-catch methods within the main method to test code

Question 18

throw keyword

Answer 18

Belongs in method body
Throw new exception(“String”)
if it is present in the method body, you must use throws in the signature

Question 19

Hoare’s Consequence

Answer 19

You can override a method by doing the following:
1. Have less or the same outputs
2. Have more or the same inputs

Question 20

Obligations and Benefits of Design by Contract

Answer 20

Client Obligations:
makes sure the inputs and legal
Client Benefits:
doesn’t have to worry about implementation
Implementor Obligations:
ensures the code works to the desired output
Implementor Benefits:
doesn’t have to worry about defensive coding

Question 21

Preconditions

Answer 21

A condition that MUST be true for your code to work (normally regarding the input the user gives)

Question 22

Postconditions

Answer 22

A condition that MUST be true for the output your code gives

Question 23

Requires

Answer 23

The formal language for Precondition

Question 24

Ensures

Answer 24

The formal language for Postcondition

Question 25

JavaDocs

Answer 25

/** Done in this style of commenting
* can be used to publish pages of Javacode with explanations
*
*
*/

Question 26

@param

Answer 26

needed for each formal parameter

Question 27

@return

Answer 27

needed for the return type/value of the variable (if there is one)

Question 28

@requires

Answer 28

formal JavaDoc for the requires statement/precondition

Question 29

@ensures

Answer 29

formal JavaDoc for the ensures statement/postcondition

Question 30

Stages of Types of Testing

Answer 30

Development Testing

Release Testing

User Testing

Question 31

Development Testing

Answer 31

When you test the code during development
includes 3 methods:
Unit testing
Component Testing
System Testing

Question 32

Unit Testing

Answer 32

When you test individual classes or methods.
Can use Automated Tests which have 3 parts:
setup
call
assertion

Question 33

Setup

Answer 33

initialize the system with the outputs and excepted inputs

Question 34

Call

Answer 34

Call a method you’re testing

Question 35

Assertion

Answer 35

Compare the real output with the expected output

Question 36

Black Box testing

Answer 36

When you know the interface but not any implementation present about code

Question 37

White Box Testing

Answer 37

when you know the implementation of code you’re testing

Question 38

Component Testing

Answer 38

testing a couple of methods/classes and how they interact with eachother

Question 39

System Testing

Answer 39

when you test the entire system to see if it works properly

Question 40

Release Testing

Answer 40

When you test a complete version to see if it meets the requirements

Question 41

User Testing

Answer 41

basically beta testing

Question 42

JUnit

Answer 42

a popular form of automatic testing
imported library
includes
@BeforeEach // used before each statement before the test
@Test // used on every test

Question 43

Simple Assertions

Answer 43

tests a boolean condition, if false, the JVM stops with an error
assert booleanExpression;

Question 44

Complex Assertions

Answer 44

Tests a boolean condition, if false, JVM stops and prints a String
assert booleanExpression: String;

Question 45

Test Driven Development

Answer 45

When you write your tests before you fill out the implementation of your program