why we not override method of HttpServlet

[Arun Maalik]

Dear sir i would like to know one thing that see as we know that in servlet HttpServlet class extends GenricServlet and as we know that both these classes are abstract and when we make any own servlet class then that should be extends HttpServlet class but as for ruls that when you extends any class that is abstract then you most override all the function of that Abstract class but here in our own servlet class we not override all the method of HttpServlet class why sir why?

[Bear Bibeault]

Originally posted by Arun Maalik:
but as for ruls that when you extends any class that is abstract then you most override all the function of that Abstract class

Not correct. In order for the extending class to not be abstract, it must supply implementations for any abstract methods in the base class -- not all the methods.

[Arun Maalik]

No sir see

 
abstract class Second {
 
  abstract public void showData1();
  abstract public void showData2();
 
  }
 
public class first extends Second{
 
   public void showData1(){
     System.out.println("Hi I m in showData1");
     }
 
   public static void main(String\u005B\u005D args){
 
      first p=new first();
      p.showData1();
 
      }
 
   }
 

when i am compiling above file using jdk1.5 then i am getting a compile time error that

error first is not abstract and doesn't define showData2 in first

Thanks

[Ben Souther]

Read Bear's post again.

it must supply implementations for any abstract methods in the base class

The HttpServlet is abstract, its methods are not.
[ September 13, 2006: Message edited by: Ben Souther ]

[Cameron Wallace McKenzie]

An abstract class can provide concrete methods. All the methods in the Servlet class we extend are concrete - it is the class itself that is abstract.

If an abstract class does not have any abstract methods, then an extending class has no obligation to override any of the inherited methods.

Isn't Java kewl?

-Cameron

[Arun Maalik]

Thanks