Inheritance

Inheritance

1. process of deriving a new class from an existing one.

2. Super class cannot access child instance data or methods unless its public.

   • Child class CAN access PUBLIC data/methods of parents
     • Child class CANNOT access PRIVATE data/methods of parent

3. Reserved word: extends

   • You can only extend ONE class.

4. protected: can only be accessed by the child of the parent class

5. Super: gives access to parent's data/methods

   • Called like: super() or super(value)
     • **If the first line in the Child's constructor is not a call to the parent class. Java implicitly places a super there. With no params**
       • Exception: a chained call to another constructor in same class will automatically defer super to that class.
         • super(xxx) --> call to parent class constructor
           • super.xxx --> call to parent class instance data
             • super.xxx() --> call to parent class method

6. Overriding:

   • When a child class defines a method w/ the same name and signature as the parent. The child version overrides the parents.
     • How to implement: @Override before the method
       • *Static methods can be inherited but NOT overriden.