diff --git a/hudi-spark/src/main/java/org/apache/hudi/QuickstartUtils.java b/hudi-spark/src/main/java/org/apache/hudi/QuickstartUtils.java
index d09716d7ad5c7..45e922f0a00ee 100644
--- a/hudi-spark/src/main/java/org/apache/hudi/QuickstartUtils.java
+++ b/hudi-spark/src/main/java/org/apache/hudi/QuickstartUtils.java
@@ -162,7 +162,7 @@ public List<HoodieRecord> generateUpdates(Integer n) throws IOException {
       String randomString = generateRandomString();
       List<HoodieRecord> updates = new ArrayList<>();
       for (int i = 0; i < n; i++) {
-        HoodieKey key = existingKeys.get(rand.nextInt(numExistingKeys - 1));
+        HoodieKey key = existingKeys.get(rand.nextInt(numExistingKeys));
         HoodieRecord record = generateUpdateRecord(key, randomString);
         updates.add(record);
       }