diff --git a/library/src/main/java/com/qiniu/android/storage/PartsUploadPerformerV2.java b/library/src/main/java/com/qiniu/android/storage/PartsUploadPerformerV2.java
index a5dd84ed..f5031ae6 100644
--- a/library/src/main/java/com/qiniu/android/storage/PartsUploadPerformerV2.java
+++ b/library/src/main/java/com/qiniu/android/storage/PartsUploadPerformerV2.java
@@ -13,8 +13,6 @@
 import java.util.List;
 import java.util.Map;
 
-import kotlin.jvm.Synchronized;
-
 class PartsUploadPerformerV2 extends PartsUploadPerformer {
 
     PartsUploadPerformerV2(UploadSource uploadSource,