Basic setup for implementing interfaces. 

        
      //  Drawable.java
      package akaan.territory.util;  
      import java.util.Vector;

      public interface Drawable {
        public void refresh ( Object arg, Vector data);
       } 

Also interfaces can inherit functionality from another interface, for instance: 

      //  Fillable.java
      package akaan.territory.util;  
      import java.util.Vector;

      public interface Fillable extends Drawable {
        public void fill ( Object arg, Color c);
       } 

When we implement the Fillable interface we have to create a method for fill and refresh.