我正在学习接口，并创建了以下程序来测试我创建的接口：

public class InterfaceTestClass {
    public static void main(String[] args) {
        InterfaceTestClass x = new InterfaceTestClass();
        Object[] foodItems = { new Apple(),x.new Chicken(),x.new Tiger() };
        for (int i = 0; i < foodItems.length; i++) {
            if (foodItems[i] instanceof Edible) {
                ((Edible) (foodItems[i])).howToEat();
            }
            if (foodItems[i] instanceof Tiger) {
                ((Tiger) (foodItems[i])).howToEat();
            }

        }
    }

    public interface Edible {
        void howToEat();
    }

    public class Apple implements Edible {
        @Override
        public void howToEat() {
            System.out.println("Eat apple as salad");
        }
    }

    public class Chicken implements Edible {

        @Override
        public void howToEat() {
            System.out.println("Eat Chicken with rice");
        }

    }

    public class Tiger {
        public void howToEat() {
            System.out.println("This is not edible");
        }
    }
}

如果我不将'x'放在'new Apple（）'或Chiken或Tiger之前，则会收到与该问题标题中的错误消息相同的错误消息。为什么会这样？

Object[] foodItems = { x.new Apple(),x.new Tiger() };