Definitions

Class - A program entity that represents either a template for a new type of object

Object - An entity that combines state and behavior

Object-oriented programming(OOP) - Programs that perform their behavior as interactions between objects

Abstraction - A distancing between ideas and details

Field - A variable inside an object that is part of its state

Declaration Syntax:

type name;

Accessing an object's fields

variable.field 

Modifying an object's fields

variable.field = value

null - A value that does not refer to any object

dereference - To access data or methods of an object with dot notation, such as s.length() (It is illegal to derefence null)

Instance method(object method) - Exists inside each object of a class and gives behavior to each object

Syntax:

public type name(parameters) {

statements;

}

Implicit parameter - The object to which an instance method is called

accessor - A method that lets clients examine object state

mutator - A method that modifies an object's state

constructor - Initializes the state of new objects

public type(parameters){

statements;

}

Encapsulation - Hiding implementation details from clients

private fields - A field that cannot be accessed from outside the class

Syntax:

private type name;

this - Refers to the implicit parameter inside your class

Refer to a field: this.field

Call a method: this.method(parameters);

One constructor can call another: this(parameters);

shadowing - 2 variables with same name in same scope

(Normally illegal,except when one variable is a field)

module - A resuable piece of software, stored as a class

static - Part of a class, rather than part of an object.

Not copied into each object; shared by all objects of that class

static fields - stored in the class instead of each object

A "shared" field all objects can access and modify

syntax:

private static type name;

private static type name = value;