--- 
+++ 
@@ -60,7 +60,7 @@
             _annotations = new HashMap<Class<? extends Annotation>,Annotation>();
         }
         Annotation previous = _annotations.put(ann.annotationType(), ann);
-        return (previous != null) && previous.equals(ann);
+        return previous == null ||!previous.equals(ann);
     }
 }
 