diff --git a/w6/Animal.java b/w6/Animal.java
new file mode 100644
index 0000000..5e7073b
--- /dev/null
+++ b/w6/Animal.java
@@ -0,0 +1,42 @@
+package w6;
+
+public abstract class Animal{
+    public abstract void makeSound();
+    public interface Swimmable{
+        void swim();
+        public class Dog extends Animal implements Swimmable{
+            @Override
+            public void makeSound(){
+                System.out.println("汪汪汪！");
+            }
+                @Override
+                public void swim(){
+                    System.out.println("狗会游泳");
+                }
+            }
+            public class Cat extends Animal {
+                @Override
+                public void makeSound() {
+                    System.out.println("喵喵喵！");
+                }
+            }
+            public class AnimalTest {
+                public static void main(String[] args) {
+                    Animal dog = new Dog();
+                    Animal cat = new Cat();
+                    System.out.println("===动物叫声测试===");
+                    dog.makeSound();
+                    cat.makeSound();
+                    System.out.println("===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");
+                    }
+                }
+            } 
+    }
+}  
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