diff --git a/carrera-sdk/producer/java/carrera-producer-sdk/src/main/java/com/xiaojukeji/carrera/producer/CarreraProducerBase.java b/carrera-sdk/producer/java/carrera-producer-sdk/src/main/java/com/xiaojukeji/carrera/producer/CarreraProducerBase.java
index e85e619..8205e8d 100644
--- a/carrera-sdk/producer/java/carrera-producer-sdk/src/main/java/com/xiaojukeji/carrera/producer/CarreraProducerBase.java
+++ b/carrera-sdk/producer/java/carrera-producer-sdk/src/main/java/com/xiaojukeji/carrera/producer/CarreraProducerBase.java
@@ -261,10 +261,11 @@ public Result sendBatchConcurrently(List<Message> messages) {
         }
         Map<Long, List<Message>> msgMap = new HashMap<>();
         for (Message msg : messages) {
-            List<Message> msgList = msgMap.get(msg.getHashId() % config.getBatchSendThreadNumber());
+            Long key = msg.getHashId() % config.getBatchSendThreadNumber();
+            List<Message> msgList = msgMap.get(key);
             if (msgList == null) {
                 msgList = new ArrayList<>();
-                msgMap.put(msg.getHashId(), msgList);
+                msgMap.put(key, msgList);
             }
             msgList.add(msg);
         }
@@ -608,4 +609,4 @@ private DelayResult sendDelayMessage(DelayMessage message) {
         }
         return result;
     }
-}
\ No newline at end of file
+}