Inheritance and Polymorphism

Inheritance and Polymorphism

1. Superclass and Subclass

   • A superclass has instance variables and methods that are general to all subclasses
     • class SavingsAccount extends BankAccount
       • SavingsAccount is a BankAccount
   • Constructors
     • Instance variable initialization
     • may
       • Call to a constructor of the superclass explicitly in the constructor of the subclass.
   • Member Accessibility
     • Are
       • Public
       • Private
       • Protected
       • Package visibility

2. Abstract Superclasses

   • have
     • Abstract Methods
       • Method without implementation
       • can be
         • overwritten
       • public abstract void CalculateBalance ();
   • no instances can be created
   • abstract class BankAccount

3. OBJECT ORIENTED PROGRAMMING

   • Interface
     • Is
       • Data type
     • have
       • Signature of methods
     • class SavingsAccount extends BankAccount implements transfer

4. Polymorphism

   • is
     • multiple answers a call