diff --git a/src/com/wentch/redkale/util/Attribute.java b/src/com/wentch/redkale/util/Attribute.java
index 564739344..354977837 100644
--- a/src/com/wentch/redkale/util/Attribute.java
+++ b/src/com/wentch/redkale/util/Attribute.java
@@ -19,9 +19,9 @@ import jdk.internal.org.objectweb.asm.Type;
  */
 public interface Attribute<T, F> {
 
-    public Class type();
+    public Class<? extends F> type();
 
-    public Class declaringClass();
+    public Class<T> declaringClass();
 
     public String field();