Pylomorphism

Object-Oriented Programming (OOP) Concepts

• Account class: has instance variable name (String), setter, getter, and is required for demonstrating private vs public access modifiers.
• Driver class: Lecture2 uses a Scanner for receiving user input, instantiates an Account object, and calls setters and getters.
• UML: represents a class with three compartments - top (class name), middle (attributes), and bottom (methods); access modifiers are represented using +/- symbols.

Constructors

• Constructor syntax: special method with the same name as the class, used for initializing objects.
• No return value for constructors; default constructors can be used if no constructor is defined.
• Constructors are invoked when an object is created, and can be used to initialize objects with default values.

Object-Oriented Programming Features

• Encapsulation: the process of hiding an object's details from other objects, providing a way to define a portable application, and leading to APIs, reusability, and abstraction.
• Polymorphism: the ability of an object to take on multiple forms, achieved through method overriding or method overloading.
• Abstraction: the process of finding commonalities between objects, resulting in a hierarchy of superclass-subclass, and enabling inheritance and polymorphism.
• Inheritance: the process of creating a new class based on an existing class, using the extends keyword, and inheriting attributes and methods.
• Package: a way to organize related classes and interfaces.

Encapsulation

• Encapsulation helps by hiding object details, preventing unexpected changes to data, and providing a way to define a portable application.
• It leads to abstraction, modularity, easier maintenance, and reusability.

Abstraction

• Abstraction helps by creating a hierarchy of superclass-subclass, enabling inheritance and polymorphism.
• It allows for the definition of an abstract behavior to represent common behavior of subclasses.

Objects, Attributes, and Behaviors

• An object is an entity in real-life with distinct states and behaviors.
• Objects have control over their member functions and data, and can hide internal members from outsiders.
• Well-intended outsiders can't make unwanted mistakes, and evil-intended outsiders have more difficulty hacking the code.

Inheritance

• Inheritance enables the creation of new classes from existing classes, using the extends keyword.
• The subclass inherits all members of the superclass, including fields and methods.
• Private members of the superclass are not visible in the subclass, but can be overridden.

Access Modifiers

• Private: only accessible within the class itself.
• Protected: accessible within the class and its subclasses.
• Package (default): accessible within the same package.
• Public: accessible from anywhere.

Static Keyword

• Static variables and methods are part of the class itself, shared by all objects of the class.
• Static members can be used before any objects are created, and should be referenced by the class name itself.
• Instance members do not exist until an object is created, and are accessed through a reference to the object.

Inheritance and Polymorphism

• Inheritance enables polymorphism, where objects of a subclass can be treated as objects of the superclass.
• Polymorphism allows for the creation of objects that can take on multiple forms, achieved through method overriding or method overloading.