diff --git a/storage/src/main/java/com/zfoo/storage/manager/StorageObject.java b/storage/src/main/java/com/zfoo/storage/manager/StorageObject.java
index 6247b5a5..e8dc15bb 100644
--- a/storage/src/main/java/com/zfoo/storage/manager/StorageObject.java
+++ b/storage/src/main/java/com/zfoo/storage/manager/StorageObject.java
@@ -32,7 +32,6 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.stream.Collectors;
 
 /**
  * @author godotg
@@ -172,12 +171,12 @@ public class StorageObject<K, V> implements IStorage<K, V> {
 
     @Nullable
     @Override
-    public <INDEX, V> V getUniqueIndex(Func1<V, ?> func, INDEX key) {
+    public <UINDEX> V getUniqueIndex(Func1<V, ?> func, UINDEX key) {
         String uniqueIndexName = LambdaUtils.getFieldName(func);
         var indexValueMap = uniqueIndexMap.get(uniqueIndexName);
         AssertionUtils.notNull(indexValueMap, "There is no a unique index for [uniqueIndexName:{}] in the static resource [resource:{}]", uniqueIndexName, clazz.getSimpleName());
         var value = indexValueMap.get(key);
-        return (V) value;
+        return value;
     }
 
     @Override
diff --git a/storage/src/main/java/com/zfoo/storage/model/IStorage.java b/storage/src/main/java/com/zfoo/storage/model/IStorage.java
index 4c597134..3d5c2f69 100644
--- a/storage/src/main/java/com/zfoo/storage/model/IStorage.java
+++ b/storage/src/main/java/com/zfoo/storage/model/IStorage.java
@@ -53,7 +53,7 @@ public interface IStorage<K, V> {
     <INDEX> List<V> getIndexes(Func1<V, ?> function, INDEX key);
 
     @Nullable
-    <INDEX, V> V getUniqueIndex(Func1<V, ?> function, INDEX key);
+    <UINDEX> V getUniqueIndex(Func1<V, ?> function, UINDEX key);
 
     int size();
 }