diff --git a/problems/0724.寻找数组的中心索引.md b/problems/0724.寻找数组的中心索引.md
index bf989979..09966e05 100644
--- a/problems/0724.寻找数组的中心索引.md
+++ b/problems/0724.寻找数组的中心索引.md
@@ -67,6 +67,24 @@ public:
 ## Java
 
 ```java
+class Solution {
+    public int pivotIndex(int[] nums) {
+        int sum = 0;
+        for (int i = 0; i < nums.length; i++) {
+            sum += nums[i]; // 总和
+        }
+        int leftSum = 0;
+        int rightSum = 0;
+        for (int i = 0; i < nums.length; i++) {
+            leftSum += nums[i];
+            rightSum = sum - leftSum + nums[i]; // leftSum 里面已经有 nums[i]，多减了一次，所以加上
+            if (leftSum == rightSum) {
+                return i;
+            }
+        }
+        return -1; // 不存在
+    }
+}
 ```
 
 ## Python
@@ -90,4 +108,3 @@ public:
 * 知识星球：[代码随想录](https://mp.weixin.qq.com/s/QVF6upVMSbgvZy8lHZS3CQ)
 <div align="center"><img src=../pics/公众号.png width=450 alt=> </img></div>
 
-