Primitive Data Types

Question 1

Double

Answer 1

8 bytes, 10^308 range

Question 2

Float

Answer 2

4 bytes, 10^38 range

Question 3

Long

Answer 3

8 bytes, 10^18 range

Question 4

Short

Answer 4

2 bytes, 10^4 range

Question 5

Char

Answer 5

2 bytes

Question 6

Automatic conversion

Answer 6

automatic: small -> big

Question 7

Type Cast

Answer 7

big range -> small range

Question 8

Variables

Answer 8

location in memory that stores data

Question 9

Condition

Answer 9

A question with 2 answers: true or false

Question 10

Break

Answer 10

When executed, inner most loop that contains the break statement will be exited immediately

Question 11

Continue

Answer 11

When executed, remainder of current iteration will be skipped

Question 12

String

Answer 12

a data type that stores a sequence if characters. OBJECT type NOT data

Question 13

StringBuilder

Answer 13

Another type to represent String info but is mutable (can be changed)

Question 14

Pre-Increment/Decrement

Answer 14

++var (increments, then returns var)

Question 15

Post-Decrement/Increment

Answer 15

var++ (returns var, increments)

Question 16

Stack

Answer 16

Variables that are created in the main or other methods. References are on the stack

Question 17

Heap

Answer 17

New objects

Question 18

Parameters

Answer 18

Variables that are part of the function being called

Question 19

Arguments

Answer 19

Values that are passed in when a function call happens

Question 20

Stack Frames

Answer 20

1. Created with each method call
2. local variables and formal parameters are stored
3. then destroyed after return

Question 21

Overloading

Answer 21

If two methods have the same name, but different signatures. Compiler selects proper method when calling overloaded method.

Question 22

Scope of Variables

Answer 22

The region in your code that you can use this variable. Defined by the block it is declared in.
- objects exist in the heap
- method calls go from one stack frame to another
- variables may have the same name but exist in different stack frames
- instance variables and local variables may have the same name

Question 23

Function Call Tracing

Answer 23

When a function is called, a stack frame is created and for all local vars. When done, it is destroyed

Question 24

Arrays

Answer 24

Objects that are dynamically created. May be assigned to variables of type Object. In the HEAP

Question 25

Are Arrays Static?

Answer 25

Yes, they remain the same size once created

Question 26

ArrayLists

Answer 26

Like StringBuilder, AL allow to grow and shrink their size.
They are designed to store references to Objects

Question 27

Formatted File Input

Answer 27

Most Important Steps:
1. Know the format (data type and layout)
2. How the data will be used (what kind if variables will be used)
3. Create objects to read file

Question 28

Object Oriented Programming (OOP)

Answer 28

Encapsulates into objects:
- data/state
- methods
Provide info hiding by separating implementation and interface

Question 29

Implementation

Answer 29

Details hidden within the object

Question 30

Private Instance Variables/Methods

Answer 30

Part of implementation

Question 31

Interfaces

Answer 31

Allow objects to know how to communicate with one another

Question 32

Public Methods and Constructors

Answer 32

Part of interface

Question 33

Class

Answer 33

Unit of defining types
- encapsulates data (instance variables) and behaviors (methods)
- object instantiation (keyword NEW) and initialized by a constructor
- class name is a new type

Question 34

Instance Variables

Answer 34

Variables defined outside a method/ctor but within the class definition
- usually PRIVATE

Question 35

Class Variables

Answer 35

Variables defines using keyword STATIC (variable shared among all the objects that type
- public static class variables can be accessed by an object

Question 36

Local Vars

Answer 36

defined in a method body
- CANNOT be public, probate, protected or static

Question 37

Encapsulation

Answer 37

Data and methods

Question 38

Inheritance

Answer 38

Keyword IMPLEMENTS (interface) and EXTENDS (implementation)

Question 39

Polymorphism

Answer 39

Allows values if different data types to be handled using a uniform interface

Question 40

Abstraction

Answer 40

Factoring out details so an object can be easily used without knowledge of how it works

Question 41

Composition of classes

Answer 41

The idea if having one class be a data member or instance variable if another. HAS-A relationship

Question 42

Superclass

Answer 42

Inherits attributes and behaviors of an existing class

Question 43

Subclass

Answer 43

embellish these with new/different capabilities in a new class

Question 44

Subclass and Superclass

Answer 44

Subclass object is a superclass object relationship NOT THE OTHER WAY AROUND
- HAS-A relationship
- superclass members become members of the subclass

Question 45

Composition vs Inheritance

Answer 45

Inheritance:
- IS-A relationship
- create nee classes by extending

Question 46

What to do in Subclass

Answer 46

• inherits all public and private members
• can replace, hide, or supplement them with new members (override)

Question 47

This

Answer 47

Used in class to indicate that calling object reference

Question 48

Super

Answer 48

Used in a class to indicate that we call the super object’s method

Question 49

Public

Answer 49

• Accessed by an Java code
• Define public interface of the class

Question 50

Private

Answer 50

• Only accessed when it occurs within the class
• instance vars
• often utility or helper methods

Question 51

Protected

Answer 51

Access is permitted
1. from within the same package
2. Or within a subclass

Question 52

Constructors

Answer 52

Methods that are called automatically to initialize instance vars for objects
- same name as class
- no return type
- never inherited, no hiding/overriding
- public, private, protected

Question 53

Abstract Classes

Answer 53

• IS-A relationship
• Cannot create instances of objects of abstract classes