Extra property is returned when using jsonview in Spring mvc4 -

i using spring mvc(4.x) , met strange problem:

@requestmapping("/xx") class controller{      @requestmapping(produce="application/json")     public resource list(@requestparameter string key, @requestparameter page page){         arraylist list=.....         return new resource(list,page);     } }  class page{     int page;     int size;     ... }  class resource<t>{   private list<t> list;   private page page;   //getter , setter omitted } 

once call:

http://.../xx/?key=key&page=1&size=10

i got json result,however looks this:

{     page:...     resource:{         list:...         page:...     } } 

i wonder why page property @ root returned?