@Entity
@Table(name = "FOLDER")
public class Folder {
  @Id
  @Column(name = "ID")
  @GeneratedValue(strategy=GenerationType.IDENTITY)
  private Integer id;

  @Formula("(select case when c.TYPE = 'M' then isnull(c.FIRSTNAME + ' ', '') + c.LASTNAME end" +
    " from CONTACT c where c.ID_FOLDER = ID")
  private String masterContact

  // getters / setters
}

WITH query AS (select
         count(folder0_.id) as col_0_0_,
     ROW_NUMBER() OVER (
 ORDER BY
     CURRENT_TIMESTAMP) as __hibernate_row_nr__ 
 from
     folder folder0_ 
 group by
     count(folder0_.id)) SELECT
     * 
 FROM
     query 
 WHERE
     __hibernate_row_nr__ >= ? 
         AND __hibernate_row_nr__ < ?

WITH query AS (select
         folder0_.id as id1_62_,
             (select
                 case 
                    when c.TYPE = 'M' then isnull(c.FIRSTNAME + ' ', '') + c.LASTNAME
                 end,
                 ROW_NUMBER() OVER (
             order by
                 folder0_.id asc) as __hibernate_row_nr__ 
             from
                 contact c
             where
                 c.id_folder = folder0_.id) as formula0_ 
         from
             folder folder0_ ) SELECT
     * 
 FROM
     query 
 WHERE
     __hibernate_row_nr__ >= ? 
         AND __hibernate_row_nr__ < ?

WITH query AS (select
         folder0_.id as id1_62_,
             (select
                 case 
                    when c.TYPE = 'M' then isnull(c.FIRSTNAME + ' ', '') + c.LASTNAME
                 end
             from
                 contact c
             where
                 c.id_folder = folder0_.id) as formula0_,
             ROW_NUMBER() OVER (
         order by
             folder0_.id asc) as __hibernate_row_nr__ 
         from
             folder folder0_ ) SELECT
     * 
 FROM
     query 
 WHERE
     __hibernate_row_nr__ >= ? 
         AND __hibernate_row_nr__ < ?