d2-d3 - OOPS Pillars and Java Classes

inheritance

polymorphism

encapsulation

abstraction

four pillars of OOP

inheritance

allows a new class (child) to inherit the properties of an existing class (parent), promoting code reuse

polymorphism

ability of an object to take on many forms, eg. shape can be circle or square

enscapsulation

hiding internal data by using access modifiers like private and public to protect integrity

abstraction

hiding complex implementation details and showing only the necessary features to users

superclass

the existing class being inherited from

subclass

the new class that inherits the features

inheritance

allows a subclass to acquire the methods and fields of a superclass

polymorphism

means “many forms” it occurs when different classes are related by inheritance but perform the same action in different ways

encapsulation (data protection)

is the bundling of data (fields) and the methods that operate on that data into a single unit or class, used for data hiding to keep vars safe from outside inheritance

true data hiding

achieved by making fields private and providing public getter and setter methods to control access

method

a block of code that performs a specific task and only runs when it is called

standard library methods ( - built in methods like touppercase)

user-defined methods (- created by the programmer)

types of methods

method definition

method call

parameter passing

execution

return value

method flow visualization