Sunday 23 October 2016


Java Inheritance

Inheritance bulletin points
  • Creating new classes from already existing classes is called Inheritance.
  • Advantage is newly deriving classes will get the all public features from existing classes.
  • Newly deriving classes are called sub/child class.
  • Existing classes are called as super/parent class.
  • java.lang.Object class is the super class for every predefined and user defined classes.
  • Without inheritance we can write even single Hello World program also.
  • private data of super class can not be inherit to sub class.
  • extends keyword is used to inherit the variables and methods from Parent class to child class.
  • One class can extends only one class at a time, because Java does not support multiple inheritance
           class Parent
                  Assuming that Parent class holding 10 public features;
           class Child extends Parent
                  Assuming that Child class holding 5 public features;
                  So finally Child class having 15 public features including Parent features;
  • Assuming that classes A extends BB extends CC extends D, here creating object for D class is good, because D class is holding all the features of super classes.
    • If we create an object to parent class then we can access only parent class data but not child class data.
    • If we create an object to child class then we can get both parent and child classes data.
Thanks for your time.