title: hibernate could not get next sequence value
body: <p>i have gwt application connect to postgres DB at the backend, and a java class 'Judgement' mapping the table 'judgements' in DB, when i tried to persistent a judgement into db, it threw the following errors:</p>
  
  <pre><code>Caused by: org.hibernate.exception.SQLGrammarException: could not get next sequence value
  ...
  Caused by: org.postgresql.util.PSQLException: ERROR: relation "hibernate_sequence" does not exist
  </code></pre>
  
  <p>my Judgement class looks like this</p>
  
  <pre><code>@Entity
  @Table(name = "JUDGEMENTS")
  public class Judgement implements Serializable, Cloneable {
  
      private static final long serialVersionUID = -7049957706738879274L;
  
      @Id
      @GeneratedValue(strategy = GenerationType.AUTO)
      @Column(name = "JUD_ID")
      private Long _judId;
  ...
  </code></pre>
  
  <p>and my table judgements is: </p>
  
  <pre><code>   Column    |            Type             |                        Modifiers                        
  -------------+-----------------------------+---------------------------------------------------------
   jud_id      | bigint                      | not null default nextval('judgements_id_seq'::regclass)
   rating      | character varying(255)      | 
   last_update | timestamp without time zone | 
   user_id     | character varying(255)      | 
   id          | integer                     | 
  Indexes:
      "judgements_pkey" PRIMARY KEY, btree (jud_id)
  Foreign-key constraints:
      "judgements_id_fkey" FOREIGN KEY (id) REFERENCES recommendations(id)
      "judgements_user_id_fkey" FOREIGN KEY (user_id) REFERENCES users(user_id)
  </code></pre>
  
  <p>and i have a SEQUENCE name 'judgements_id_seq' in DB</p>
  
  <p>can anyone tell me what's wrong??? thanks.</p>