多态

class Bread{
    Bread(){
        System.out.println("Bread()");
    };
}
class Cheese{
    Cheese(){
        System.out.println("Cheese()");
    }
}
class Lettuce{
    Lettuce(){
        System.out.println("Lettuce()");
    }
}
class Lunch extends Lettuce{
    Lunch(){
        System.out.println("Lunch()");
    }
}
class PortableLunch extends Lunch{
    PortableLunch(){
        System.out.println("PortableLunch()");
    }
}
class Meal{
    Meal(){
        System.out.println("Meal()");
    }
}
public class Sandwich  extends PortableLunch{
    private Bread b=new Bread();
    private Cheese c=new Cheese();
    private Lettuce l=new Lettuce();
    public Sandwich(){
        System.out.println("Sandwich");
    }
    public static void main(String[] args) {
        new Sandwich();
        System.out.println("//////////////////////执行后面的类///////////////////////");
    }
}