inheritance in Java

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