diff --git a/boot-service/src/main/java/com/xwbing/demo/LambdaDemo.java b/boot-service/src/main/java/com/xwbing/demo/LambdaDemo.java
index bcf687a..4739f80 100644
--- a/boot-service/src/main/java/com/xwbing/demo/LambdaDemo.java
+++ b/boot-service/src/main/java/com/xwbing/demo/LambdaDemo.java
@@ -98,7 +98,7 @@ public class LambdaDemo {
         CompletableFuture[] futures = new CompletableFuture[size];
         List<Integer> finalList = new ArrayList<>(size);
         for (int i = 0; i < size; i++) {
-            finalList.add(null);//必须有这步，否则会下标越界
+            finalList.add(null);//在异步之前size+1，必须有这步，否则会下标越界
             Integer integer = list.get(i);
             final int pos = i;
             futures[i] = CompletableFuture.supplyAsync(() -> finalList.set(pos, integer), taskExecutor);//按原来顺序存
diff --git a/boot-service/src/main/java/com/xwbing/demo/demo.java b/boot-service/src/main/java/com/xwbing/demo/demo.java
index 66136af..36ea27c 100644
--- a/boot-service/src/main/java/com/xwbing/demo/demo.java
+++ b/boot-service/src/main/java/com/xwbing/demo/demo.java
@@ -21,6 +21,7 @@ public class demo {
         CompletableFuture[] futures = new CompletableFuture[size];
         List<Integer> finalList = new ArrayList<>();
         for (int i = 0; i < size; i++) {
+            finalList.add(null);
             Integer integer = list.get(i);
             int finalI = i;
             futures[i] = CompletableFuture.supplyAsync(() -> finalList.set(finalI, integer));