cglib annotation extends problem analysis

cglib not write method Attribue into subclass:
Enhancer->generateClass(ClassVistor c)->ReflectUtils.getMethodInfo(Method method,modifiers)->Attribute getAttribute(){ return null}
http://today.java.net/pub/a/today/2005/11/01/implement-proxy-based-aop.html
http://aspectwerkz.codehaus.org/new_features_in_2_0.html
http://blog.springframework.com/rod/

http://sixlegs.com/blog/java/async-annotations.html
http://www-128.ibm.com/developerworks/cn/java/j-cwt06075/
http://www.onjava.com/pub/a/onjava/2004/10/20/asm.html?page=1