Marker interface example-

public interface Serializabale {}

public interface Cloneable {}

Also known as 'Tagging' interface.

1.>in general tagged or marker interface is used to just identify the class in real time projects there are so many classes in order to identify which class belongs to which module this tag or marker interface is useful.

2.>

in serialization also if we want to serialize the object first it will internally checks whether the class is implementing java.io.serializable interface by using instanceof operator.

3.>in rmi also every remote class should implement java.rmi.remote interface.

public interface csedept{

}

public class computer implements csedept{

int no;

String name;

}

public class Sample

{

computer c new computer();

if(c instanceof csedept)

{

c.name computer science course ;

}

}