// Flyable interface
              interface Flyable {
                  void fly_obj();
              }
              
              // Spacecraft class implementing Flyable interface
              class Spacecraft implements Flyable {
                  @Override
                  public void fly_obj() {
                      System.out.println("Spacecraft is flying in space.");
                  }
              }
              
              // Airplane class implementing Flyable interface
              class Airplane implements Flyable {
                  @Override
                  public void fly_obj() {
                      System.out.println("Airplane is flying in the sky.");
                  }
              }
              
              // Helicopter class implementing Flyable interface
              class Helicopter implements Flyable {
                  @Override
                  public void fly_obj() {
                      System.out.println("Helicopter is flying in the air.");
                  }
              }
              
              class fly{
                  public static void main(String[] args) {
                      // Create objects of each class and call fly_obj() method
                      Spacecraft sc = new Spacecraft();
                      Airplane ap = new Airplane();
                      Helicopter hc = new Helicopter();
              
                      // Call fly_obj() method for each object
                      sc.fly_obj();
                      ap.fly_obj();
                      hc.fly_obj();
                  }
              }