identifier of an instance of Address was altered from 5 to 4 (org.hibernate.HibernateException:)

I Had Assigned The Value To The  Parent's Child Object Id as
Student studentObj=new Student();
StudentDAO daoStudent=new StudentDAO();

studentObj=daoStudent.LoadById(studentBE.StudentId);

studentObj.Address.AddressId=studentBE.AddressId;

Then I Had Got The Exception "Identifier Of An Instance Of Address Was Altered From 5 to 4".
An NHibernateException.


Solution:-
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By Creating A New Object Of Address With The Given Id And Replacing The Address Object Associated With Object Student -- as below:

studentObj.Address=new Address(){AddressId=studentBE.AddressId};