Hi, An interface which contains no methods or member variables will be called as Marker Interface. For eg:- Remote, Serializable or marker interfaces. Why because, the compiler will check whether that class is an instance of that interface ( for eg:- serializable) and if it is true means, it will serialize that object.
A Marker interface is used to indicate that a class can be used for a specific purpose. Look at the Serializable interface, it actually has no methods that you have to implement. But it indicates that a class that implements this interface can be (de)serialized (converted to a byte representation).
If you, for instance, want to save an object to disk using an ObjectOutputStream, only objects that implement the Serializable interface can be saved.