org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session: [com.hornsandhooves.db.entity.DivisionImpl#28]

if(divisionDao.read(divisionForm.getId()) == null) {
            return false;
        } else {
divisionDao.getSession().update((DivisionImpl) division);
          return true;

if(divisionDao.read(divisionForm.getId()) == null) {
            return false;
        } else {
divisionDao.update((DivisionImpl) division);
          return true;

public class DaoImpl <T, PK extends Serializable> implements IDao <T, PK> {
    
    private Class<T> type;
    
    @Autowired
    private SessionFactory sessionFactory;
    
    
    public DaoImpl(Class<T> type) {
        this.type = type;
    }
    
    public PK create(T o) {
        return (PK) getSession().save(o);
    }
    
    public T read(PK id) {
        return (T) getSession().get(type, id);
    }
    
    public void update(T o) {
        getSession().update(o);
    }
    
    public void delete(T o) {
        getSession().delete(o);
    }

    
    public List<T> findAll() {
        return  getSession().createQuery("from " + type.getName()).list();
    }
    
    /**
     * Возвращает текущую сессию hibernate
     * @return sessionFactory.getCurrentSession()
     */
    public Session getSession() {
        return sessionFactory.getCurrentSession();
    }
    
    public T getInstace() throws java.lang.InstantiationException, IllegalAccessException {
        return type.newInstance();
    }

public class DivisionDao extends DaoImpl<DivisionImpl, Long> {
    
    /**
     * Конструктор инициализирует супер класс
     */
    public DivisionDao() {
        super(DivisionImpl.class);
    }
}

IDivision division = divisionDao.read(divisionForm.getId());
if(division == null) {
    return false;
} else {
    division.setTitle(divisionForm.getTitle().trim().replaceAll("<", "&#60;"));
    divisionDao.getSession().update((DivisionImpl) division);
    return true;