diff --git a/javaSE-day04/src/com/inmind/interface_return03/ArraysDemo13.java b/javaSE-day04/src/com/inmind/interface_return03/ArraysDemo13.java
new file mode 100644
index 0000000..6bd2bbf
--- /dev/null
+++ b/javaSE-day04/src/com/inmind/interface_return03/ArraysDemo13.java
@@ -0,0 +1,30 @@
+package com.inmind.interface_return03;
+
+import java.util.Arrays;
+import java.util.Comparator;
+
+/*
+Arrays工具类
+    public static String toString(int[] a) ：返回指定数组内容的字符串表示形式。
+    public static void sort(int[] a) ：对指定的 int 型数组按数字升序进行排序。
+ */
+public class ArraysDemo13 {
+    public static void main(String[] args) {
+        String[] arr = {"aa", "ab", "da", "cd"};
+        Integer[] arr1 = {100, 22, 14, 33, 200};
+
+        Arrays.sort(arr);
+        Arrays.sort(arr1);
+        System.out.println(Arrays.toString(arr));
+        System.out.println(Arrays.toString(arr1));
+
+        Arrays.sort(arr1,new Comparator<Integer>(){
+
+            @Override
+            public int compare(Integer o1, Integer o2) {
+                return o2 - o1;
+            }
+        });
+        System.out.println(Arrays.toString(arr1));
+    }
+}