Regarding Marker Interface?

[V. Potluri]

Hi,

As I know that market interface doesn't contain any methods or variables.
But JVM provides extra capability to the class that implements marker interface. For example, we can create clone of an object if it's class implements Clonable interface. Otherwise we cannot create clone of an object. Violating above rule raises runtime exception called CloneNotSupportedException.

Can we call Comparator interface as an marker interface eventhough it is having abstract method called compare. The signature of comapare in Comparator interface is as follows:

 
 
   interface Comparator {
      int compare(java.lang.Object obj, java.lang.Object obj); 
   }
 

1. Can we call Comparator interface as marker interface?
2. Is any interface in java ,with methods called as marker interface?

Waiting for reply. Thanks in advance!

Have a wonderful day ahead!

Regards,
Gopal

[Ulf Dittmer]

But JVM provides extra capability to the class that implements marker interface.

Let's be precise: some code somewhere provides the extra functionality. Often it's in the class libraries -not the JVM- (like for Serializable and Cloneable), but if you were to define a marker interface, then your code would have to implement its special functionality.

Can we call Comparator interface as marker interface?

Is any interface in java ,with methods called as marker interface?

No and no. Why would they? Marker interfaces are specifically those without methods.