• Consider a Java Class → Employee

  

  • Two private instance variables → name, salary.
  • A public method to compute bonus.
  • Constructors, Accessors and Mutators.

• A subclass would be → Manager → Special types of employees with extra features

  

  • name, salary inherited from Employee class

• Manager is a SUBCLASS of Employee

  • Think of subset.

• Manager object do not have access to private data of Employee (parent) class.

  • For Example, when we extend a parent class written by someone else (or extending a library class).

  • So , use parent class’s constructor using super keyword.

    

• Subclass has more features than parent class.
• Every Manager is an Employee , but not vice versa!!!

<aside> 💡 Can use a subclass in place of a superclass. Employee e = new Manager(...)

</aside>

• But the following will not work.

  • Manger m = new Employee(...) (Because all functionalities of Manger is not available to Employee)

• You can now write something like:

  <aside> 💡 Employee[] e = new Manager(...)[100]

  </aside>