inheritance in Java

By: Saravanan in Java Tutorials on 2010-01-01

In this tutorial we are going to see how to inherit a class. For that we simply incorporate the definition of one class into another class by using extends keyword. Now we create a superclass named parent and a subclass named child. This program displays the parent class contents, child class contents and sum of the contents.

class parent
{
 int pi,pj;
 void showpipj()
 {
  System.out.println("pi and pj:"+pi+" "+pj);
 }
}

class child extends parent
{
 int pk;
 void showpk()
 {
  System.out.println("pk:"+pk);
 }
 void sum()
 {
  System.out.println("pi+pj+pk:"+(pi+pj+pk));
 }
}

class InheritExample
{
 public static void main(String arg[])
 {
  parent p=new parent();
  child c=new child();
  p.pi=2;
  p.pj=7;
  System.out.println("contents of parent class");
  p.showpipj();
  System.out.println();
  c.pi=18;
  c.pj=27;
  c.pk=9;
  System.out.println("contents of child class");
  c.showpipj();
  c.showpk();
  System.out.println();
  System.out.println("sum of pi,pj,pk in child");
  c.sum();
 }
}

output:

contents of parent class
pi and pj:2 7
contents of child class
pi and pj:18 27
pk:9
sum of pi,pj,pk in child
pi+pj+pk:54

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