diff --git a/Animal.class b/Animal.class
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diff --git a/AnimalTest.class b/AnimalTest.class
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diff --git a/AnimalTest.java b/AnimalTest.java
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+// 1. 抽象类 Animal
+abstract class Animal {
+    // 抽象方法：动物叫
+    public abstract void makeSound();
+}
+
+// 2. 接口 Swimmable
+interface Swimmable {
+    // 游泳方法
+    void swim();
+}
+
+// 3. Dog 类：继承Animal，实现Swimmable接口
+class Dog extends Animal implements Swimmable {
+    @Override
+    public void makeSound() {
+        System.out.println("狗叫：汪汪汪 🐶");
+    }
+
+    @Override
+    public void swim() {
+        System.out.println("狗会游泳，正在刨水🏊‍♂️");
+    }
+}
+
+// 4. Cat 类：只继承Animal，不实现Swimmable
+class Cat extends Animal {
+    @Override
+    public void makeSound() {
+        System.out.println("猫叫：喵喵喵 🐱");
+    }
+}
+
+// 5. 主类（必须public，和文件名一致）
+public class AnimalTest {
+    public static void main(String[] args) {
+        // 多态：父类引用指向子类对象
+        Animal dog = new Dog();
+        Animal cat = new Cat();
+
+        // 调用叫声方法
+        System.out.println("=== 动物叫声测试 ===");
+        dog.makeSound();
+        cat.makeSound();
+
+        // 测试游泳接口：只有Dog实现了Swimmable
+        System.out.println("\n=== 游泳能力测试 ===");
+        if (dog instanceof Swimmable) {
+            ((Swimmable) dog).swim();
+        }
+        if (cat instanceof Swimmable) {
+            ((Swimmable) cat).swim();
+        } else {
+            System.out.println("猫不会游泳，只能在边上看着~");
+        }
+    }
+}
\ No newline at end of file
diff --git a/Cat.class b/Cat.class
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diff --git a/Dog.class b/Dog.class
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