Abstract class

Hi,
In an interview I have been asked a question What is the'Well known abstract class without methods'?
Please tell me, I dont know the answer for this.

Regards,
Sree

What is the'Well known abstract class without methods'?

It's called a badly designed class

I'm looking forward to the answer too.

I dont have any idea on this.
Please let me know the answer,if you get it.

Hmmm.. I had heard about few marker interfaces flying around like the java.io.Serializable interface which do not declare any methods. The abstract classes with no interfaces are called marker classes, but can't site you any example of such an interface.

Just choose a Marker interface:

I think the most "well known" are:

java.lang.Cloneable
java.io.Serializable
java.util.EventListener

For more information the following link will help you?

What is a "marker" interface?

Originally posted by Remko Strating:
Just choose a Marker interface:

I understand what you are trying to mean , but how can interface be class.The post specifically says about abstract class.

I think the question is supposed to be "abstract class without abstract methods."

It seems to be HttpServlet.

http://java.sun.com/products/servlet/2.2/javadoc/javax/servlet/http/HttpServlet.html

This is an interesting bit of trivia, but I don't see how it helps an interviewer screen you.

[ June 25, 2007: Message edited by: Bill Cruise ]

Please don't call marker interfaces abstract classes

There are interfaces. If the sridhar could bring some light on what he was asked exactly...

My question is very clear,
I am not asking about Marker/Tagged interface. "Very familiar abstract class which doesn't have any(abstract/concrete) methods".
I think now it is clear.