Java up and down transformation

First, upward transformation

Example: Parent p=new Son (); This references p can only call methods that overload the parent class in the subclass, but the property is the parent class, and the Getter () method is used if you want to invoke the subclass attribute.

Ii. Downward transformation

The parent class reference of the subclass object is assigned to the subclass reference called Downward Transformation (downcasting), to be cast, for example: Father f1 = new Son (); son S1 = (son) F1;

Java up and down transformation