Hiberante many-to-one merge
===

I have a class Person with id, name, and status . the status is a class Status with id, and status string
this is shortly the code generated by netbeans tool for hibernate

    class Person{
       long id;
       String name;
       Status status;
       //getters and setters
    }
    class Status{
       long id;
       String status;
       List<Person> persons;
       //getters and setters
    }

    
the problem is when I want to merge a person in the session I get the status null

Person p = getById(1L); // person name=XX; status=1

p.setName("YY");

session.merge(p); // here the status is get NULL 
not-null property references a null or transient value: model.Status

I know that hibernate load the person object when merging so why the status return as null;??