Java Answers Forum - Null Interface

Articles |
News |
Weblogs |
Books |
Forums

Artima Forums | Articles | Weblogs | Java Answers | News

Sponsored Link •

Java Answers Forum
Null Interface

3 replies on 1 page. Most recent reply: Sep 30, 2004 7:03 AM by Samrat Bhatnagar

Welcome Guest
Sign In

Back to Topic List

Reply to this Topic

Search Forum

Threaded View


Previous Topic		Next Topic

Flat View: This topic has 3 replies on 1 page

Gaurav

Posts: 1
Nickname: gaurav123
Registered: Sep, 2004

Null Interface

Posted: Sep 21, 2004 10:29 PM

What is null interface??? Why do we ned null interfaces???

Kondwani Mkandawire

Posts: 530
Nickname: spike
Registered: Aug, 2004

Re: Null Interface

Posted: Sep 28, 2004 3:57 PM

> What is null interface??? Why do we ned null interfaces???

I'm a little confused here. An interface simply
lists behaviour. How would there be a Null interface...
A Null Object would be a place in Memory with nothing
or that hasn't been declared or something to that
effect. However, if all that is happening in an
interface is declaration of Method signatures
to specify behaviour how would there be a Null
Interface and what would be their purpose if there
was one?

Just trying to learn like y'all guys. What
web site or book did you see this at?

Spike

Sandu Crasteti

Posts: 13
Nickname: xan
Registered: Feb, 2003

Re: Null Interface

Posted: Sep 29, 2004 2:58 AM

Hi!

I quote the Java Tutorial:

"Empty interfaces can be used as types and to mark classes without requiring any particular method implementations. For an example of a useful empty interface, see java.io.Serializable."

Have a nice day!

Samrat Bhatnagar

Posts: 2
Nickname: ironman166
Registered: Sep, 2004

Re: Null Interface

Posted: Sep 30, 2004 7:03 AM

I thought i should elaborate this topic.

Null Interfaces also know as Marker Interfaces are simply marking the class that implements them.Now when the JVM looks at such a class it allows it to call certain methods.

e.g There is a method clone() in Object class.All classes implicitly inherit this class.So we should be able to call this method when we declare a user defined class.Try doing this and the JVM will give an error.

For this the solution is that if we implement the Clonable marker interface then JVM knows that this class can call the clone() method.So now we can call clone on this class's object.

Flat View: This topic has 3 replies on 1 page

Previous Topic

Next Topic


	Web Artima.com