an object first loaded by session(eg,session.load(...,..)),if session don't close,the following load will return the same object.this means that if the first loaded object change,the following loaded object also == the first object ,not the refresh object from database!

compositeIdUser = (CompositeIdUser) session.load(CompositeIdUser.class, compositeIdUser);
compositeIdUser.setAge(new Integer(1133883)); //change the age
 compositeIdUser = (CompositeIdUser) session.load(CompositeIdUser.class, compositeIdUser);
 compositeIdUser.getAge will equals 1133883; //the second loaded object == the first!     

in two session with session-level cache ,if the first object change and saveOrUpdate ,the second object don't select from database and still use cache.because when the first object change and saveOrUpdate ,the cache also update to the latest version.