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Use of Marker Interface

Karthikeyan Ramaswamy
Ranch Hand

Joined: Apr 30, 2008
Posts: 41
hi all,

what is the use of Marker interface(interface have no methods).


above interface has no methods to implement.
so, my question is what is purpose for and how it's working.
and when we can write user-defined marker interface.
b panigrahy

Joined: Apr 11, 2006
Posts: 14
Marker interface is meant for Reference type checking

Ex. if class A implements then when you transfer object of class A using ObjectOutputStream class then it will check inside writeObject(Object obj, boolean unshared) method.

Code snippet is :
if (obj instanceof Serializable) {
writeOrdinaryObject(obj, desc, unshared);
}else {

Marker is a logical term .
Rajkamal Pillai
Ranch Hand

Joined: Mar 02, 2005
Posts: 443


It also provides functionality without the developer having to code for the same.

Ben Souther

Joined: Dec 11, 2004
Posts: 13410

"Karthikeyan R",
Please check your private messages regarding an important administrative matter.

Java API J2EE API Servlet Spec JSP Spec How to ask a question... Simple Servlet Examples jsonf
I agree. Here's the link:
subject: Use of Marker Interface