Question

What is a marker interface?

Answer 1

A Marker interface can be defined as the interface which has no data member and member functions. For example, Serializable, Cloneable are marker interfaces. The marker interface can be declared as follows.

public interface Serializable{    

}

Answer 2

An empty interface in Java is referred to as a Marker interface. Serializable and Cloneable are some famous examples of Marker Interface.