superclass by subcall in java example

Example: inheritance in java

it is used to define relationship between two class, 
which a child class occurs all the properties and
  behaviours of a parent class. 
Provides code reusability.
Ex: in my framework I have a TestBase 
class which I store 
all my reusable code and methods.
  My test execution classes and 
elements classes will extend the 
TestBase in order to reuse the code.