Implement interface in a service and call it in another class -Android -

i have use case in need update points(markers) on map when event occurs inside service. using interface callback method.

    public interface draw      {         void updatepoints(context context) throws jsonexception;     } 

now using interface in service :

draw dfc;  ............... //inside constructor of class dfc=new draw() {                 @override                 public void updatefloatingpoints(context context) throws jsonexception {                     system.out.println("callback in service");                     customviewview.registerdpclistener(dfc);                 }             }; 

now within same service, under function, passing interface input parameter i.e callback , inside function calling

callback.updatefloatingpoints(context); 

now when running service, can see callback in service statement. till here okay.

now problem that, when callback received, want work class. let's call customview. implemented interface in class not able receive callbacks on there. follow bare bone code of class

public class customview extends abcd implements draw {     private draw dfclistner=null;     public void registerdpclistener(drawpath listener) throws jsonexception {         this.dfclistner = listener;         if(dfclistner!=null)         {             system.out.println("listener initialized");             //dfclistner.updatefloatingpoints(mcontext);          }         else         {             system.out.println("listener not initialized");         }     }     //another functions in between on here      @override     public void updatefloatingpoints(context context) throws jsonexception {         system.out.println("inside customview callback");      } } 

how go it?