gistfile1.java

public class Main {                                                                                                                                                             
                                                                                
    static interface InterfaceA {                                               
        public void speak();                                                    
    }                                                                           
                                                                                
    static interface InterfaceB extends InterfaceA {                            
        public void sit();                                                      
                                                                                
    }                                                                           
                                                                                
    static class ImplementsA implements InterfaceA {                            
        public void speak() {                                                   
            System.out.println("ImplementsA");                                  
        }                                                                       
    }                                                                           
                                                                                
    static class Foo extends ImplementsA implements InterfaceB {                
        public void sit() {                                                     
            System.out.println("I am sitting");                                 
        }                                                                       
    }                                                                           
                                                                                
    public static void main(String[] args) {                                    
        System.out.println("Hello");                                            
        Foo foo = new Foo();                                                    
        foo.speak();                                                            
        foo.sit();                                                              
    }                                                                           
                                                                                
}