diff --git a/s-day03/src/com/inmind/colletions04/Demo12.java b/s-day03/src/com/inmind/colletions04/Demo12.java
new file mode 100644
index 0000000..a410421
--- /dev/null
+++ b/s-day03/src/com/inmind/colletions04/Demo12.java
@@ -0,0 +1,26 @@
+package com.inmind.colletions04;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+/*
+static <T> void sort(List<T> list) 根据其元素的自然排序，按照升序排列指定的列表。
+ */
+public class Demo12 {
+    public static void main(String[] args) {
+        //整数的自然排序：123456
+        List<Integer> lists = new ArrayList<>();
+        Collections.addAll(lists, 100, 55, 33, 66, 7, 89, 44);
+        System.out.println(lists);
+        Collections.sort(lists);//升序排序
+        System.out.println(lists);
+        //字符串的自然排序
+        List<String> strList = new ArrayList<>();
+        Collections.addAll(strList, "cb", "bb", "ab", "ba", "ca");
+        System.out.println(strList);
+        Collections.sort(strList);
+        System.out.println(strList);
+
+    }
+}