Abstract
- There are 4 core pillars in OOP - Abstraction (抽象), Inheritance, Polymorphism and Encapsulation
OOP Class
- An Abstraction (抽象) over a group of similar items that share the same properties and actions
Inner Class
- An OOP Class inside an OOP Class
Anonymous Inner Class
- A Inner Class without a name
Important
Anonymous classes are useful when you need to create a class that implements an OOP Interface or extends a class, but you don’t need to reuse the class elsewhere in your code.
OOP Object
- An actual instance of OOP Class that occupies some space in the Heap Segment
- The variable holds a memory pointer to the OOP Object, not the values inside the OOP Object
OOP Interface
- Defines a set of OOP Abstract Method that a OOP Class must implement if it chooses to implement that interface. It doesn’t provide any concrete implementations for these methods
- Focus on what a class should do rather than how it should do it
Functional Interface
- Also known as Single Abstract Method(SAM)
- OOP Interface that contains only one OOP Abstract Method
OOP Method
- The functions we specify in the OOP Class
OOP Abstract Method
- Methods declared without a body