pdj555 / java-2-cp2

Class Notes Week 4

terminology

• subclass = child class
• superclass = parent class

java.lang.Object superclasses

https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/Object.html

java.util.ArrayList

https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/ArrayList.html

stick with private

Inheritance

Occurs when a class is derivaed from another class

• the derived class inheriets the class members of the parent class
• the methods of the parent class can be used in the child class

Inheriets the rectangle class members

Polymorphism

• data types determine which program behavior to execute Objects of a parent class are required to have the parameters of the parent class; however, the objects will be of one of the child classes. Aka upcasting.

Shape can be any of the shape classes

Abstract methods

• not implimented in the base class
• for objects you must impliment abstract methods

Down casting

• first: ensure it is of a specific shape
• second: downcast

When to do downcasting:

• to use specific features of child class