Another Unit 2 (Idk What's Going On)

arguments

values that take the place of its corresponding parameter

parameters

the placeholders for values that will be fulfilled by the arguments

constructors

purpose is to initialize the fields

shadowing

when two variables of different scopes have the same name and are in memory at the same time, can be fixed with this. or different field names (like my)

overloading

2 or more methods with the same class and same name but different parameters

toString

purpose is to report the state of the object, is automatically invoked when you try to print the object reference and will print the memory location if not overridden

this () vs. this.

this. is used to access an instance field or method (but not the constructors; normally used to avoid shadowing; this() is used to access a different constructor, it must be the first line of the constructor

concatenation

the joining of two or more strings, can also join numbers to strings in a commutative manner

black box theory

private values that can only be accessed through methods that can access and retrieve the information from inside the class

method

series of instructions that implement a behavior of an object (what the object does)

class

blueprint of an object

object

the instance of a class

mutator

used to change the values that an object contains

accessor

allows the client of teh class to extract data from an objecte

errors

mistakes made in coding that prevent the code from running or returning values that are logically incorrect

questions about the scope of variables

1) where is it declared

2) who has access

3) when does it leave memory

instance fields

where the object stores it values

instatiation

the process of creating an object

variable

location in memory where value is stored

assignment operator

stores the value of the right to the left, generally using the “=” symbol

object attribute

what an object has; stored in the fields

object method

what an object does

object state

determined by the values of the fields

abstraction

understanding what something does, not how it does it

encapsulation

data and methods belong to an individual object-each object has their own methods and attribute (the grouping together of methods into one class)

parameter

the data the method needs to do its job

“new” keyword

1) creates the object

2) calls upon the constructor

default constructor

no parameters assigns default values to instance fields

parameterized constructor

has parameters that assigns values to instance fields

“camel” notation

is the practice of writing compound words or phrases such that each word or abbreviation begind to a capital letter

“humpback” notation

the first letter starts with a lowercase letter when naming

object reference

object variable, whats used to store an object

“null” keyword

releases the reference from the object

this. vs this()

this. is used to access an instance field or method in order to generally resolve errors due to shadowing

this() is used to access a different constructor; it must be the first line of the constructor

local scope characteristics

1) declared within method

2) can be in method signature (as a parameter) or the body

3) can only be accessed within the method

4) is out of scope when the method ends

class scope characteristics

1) declared in the class (not in a method)

2) variables are called instance fields

3) is out of scope when the object leaves memory/object reference goes to 0

block scope characteristics

1) declared in a block statement

2) variables are known as block variables

3) only the block has access to it

4) is out of scope when the block statement ends