Inheritance Overview

1
Inheritance Overview

• Inheritance is another one of the big OOP
  concepts
• The idea is that we can define a very general
  class and then define more specialized classes
  that inherit the attributes (data) and operations
  (methods) of the general class.

2
Derived Class and Base Class

• When we define a class that inherits data and
  methods from another class we call the class that
  inherits the derived class and the one being
  inherited from the base class.
• Example
• We may have a truck class (derived) that
  inherits data and methods from a vehicle class
  (base).

3
Method Overriding

• In some cases we may have methods in the derived
  class that have the same method signature as what
  is in the base class.
• What happens in this case is that the method in
  the derived class overrides the method in the
  base class.
• How is this different from method overloading?

4
The Class Object

• There is one class that every class is a
  descendant from and that is the predefined class
  Object.
• One of the methods in that class is called
  toString which suppose to return all the data
  (instance variables) as a String.
• Sounds nice huh? Well, it usually does not work
  the way we would like
• What can we do? Override it!