One-root-entity-per-returned-row phenomenon of hibernate

 

public static List t() ...{
        List r = new ArrayList();
        Session s = Sf.getSession();
        Transaction tx;
        tx = s.beginTransaction();
        String sql;

        try ...{
            r = s.createCriteria(JtsUser.class)
                 .add(Restrictions.idEq(2))
                 .setFetchMode("jtsHistories", FetchMode.JOIN)
                 .setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY)
                 .list();
            tx.commit();
        } catch (Exception e) ...{
            e.printStackTrace();
            tx.rollback();
        } finally ...{
            s.close();
        }
        return r;
    }
    

    public static List tt() ...{
        List r = new ArrayList();
        Session s = Sf.getSession();
        Transaction tx;
        tx = s.beginTransaction();
        String sql;

        try ...{
            r = s.createCriteria(JtsUser.class)
                 .add(Restrictions.idEq(2))
                 .setFetchMode("jtsHistories", FetchMode.JOIN)
                 .list();
            tx.commit();
        } catch (Exception e) ...{
            e.printStackTrace();
            tx.rollback();
        } finally ...{
            s.close();
        }
        return r;
    }

t().size() is 1; While tt().size() is 4, that's the one-root-entity-per-returned-row phenomenon of hibernate.

Add "setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY)" to eliminate the one-root-entity-per-returned-row phenomenon that you're seeing.