diff --git a/problems/0707.设计链表.md b/problems/0707.设计链表.md
index 2d76fffc..2fa1af29 100644
--- a/problems/0707.设计链表.md
+++ b/problems/0707.设计链表.md
@@ -158,6 +158,14 @@ private:
 
 Java：
 ```Java
+class ListNode {
+int val;
+ListNode next;
+ListNode(){}
+ListNode(int val) {
+this.val=val;
+}
+}
 class MyLinkedList {
     //size存储链表元素的个数
     int size;