diff --git a/day09/src/com/inmind/extends_override03/test/Demo04.java b/day09/src/com/inmind/extends_override03/test/Demo04.java
new file mode 100644
index 0000000..9e71d21
--- /dev/null
+++ b/day09/src/com/inmind/extends_override03/test/Demo04.java
@@ -0,0 +1,15 @@
+package com.inmind.extends_override03.test;
+/*
+重写的应用场景：手机
+重写的意义：对于父类中方法的功能的扩展
+ */
+public class Demo04 {
+    public static void main(String[] args) {
+        //买新旧手机，感受下重写的效果
+        Phone phone = new Phone();
+        phone.show();
+        System.out.println("-------");
+        NewPhone newPhone = new NewPhone();
+        newPhone.show();
+    }
+}
diff --git a/day09/src/com/inmind/extends_override03/test/NewPhone.java b/day09/src/com/inmind/extends_override03/test/NewPhone.java
new file mode 100644
index 0000000..a6a53eb
--- /dev/null
+++ b/day09/src/com/inmind/extends_override03/test/NewPhone.java
@@ -0,0 +1,14 @@
+package com.inmind.extends_override03.test;
+
+public class NewPhone extends Phone{
+   //ctrl+O 展示父类中可以重写的方法
+
+    @Override
+    public void show() {
+        //重写时，可以选择性地沿用父类的功能，然后扩展，也可以直接推翻，重新实现
+        super.show();//沿用父类的功能
+        //以下代码就是对父类功能的扩展
+        System.out.println("显示头像");
+        System.out.println("显示归属地");
+    }
+}
diff --git a/day09/src/com/inmind/extends_override03/test/Phone.java b/day09/src/com/inmind/extends_override03/test/Phone.java
new file mode 100644
index 0000000..1895423
--- /dev/null
+++ b/day09/src/com/inmind/extends_override03/test/Phone.java
@@ -0,0 +1,18 @@
+package com.inmind.extends_override03.test;
+
+public class Phone {
+    String brand;
+    String color;
+
+    public void call(String number) {
+        System.out.println("给"+number+"打电话");
+    }
+
+    public void send(String number) {
+        System.out.println("给"+number+"发短信");
+    }
+
+    public void show() {
+        System.out.println("显示电话号码");
+    }
+}