title: @GeneratedValue doesn't work. "java.sql.SQLException: Field 'ID' doesn't have a default value"
body: <p>Context: <code>Jboss5.1</code>, <code>MySql 5.0</code></p>
  
  <p>I've tried a lot of possibilities .. a simple <code>@GeneratedValue</code> or other solution specifing explicitly the sequence generator, but also have the same problem...
  There is the stack trace</p>
  
  <pre><code>22:00:53,334 INFO  [STDOUT] Hibernate: insert into Lavoro (nome, userIDrichiedente, sede, stato) values (?, ?, ?, ?)
  22:00:53,341 WARN  [JDBCExceptionReporter] SQL Error: 1364, SQLState: HY000
  22:00:53,342 ERROR [JDBCExceptionReporter] Field 'ID' doesn't have a default value
  22:00:53,372 ERROR [[CreaLavoroServlet]] Servlet.service() for servlet CreaLavoroServlet threw exception
  javax.ejb.EJBException: javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: could not insert: [org.swimv2.model.Lavoro]
      at org.jboss.ejb3.tx.Ejb3TxPolicy.handleExceptionInOurTx(Ejb3TxPolicy.java:77)
      at org.jboss.aspects.tx.TxPolicy.invokeInOurTx(TxPolicy.java:83)
      at org.jboss.aspects.tx.TxInterceptor$Required.invoke(TxInterceptor.java:190)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
      at org.jboss.aspects.tx.TxPropagationInterceptor.invoke(TxPropagationInterceptor.java:76)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
      at org.jboss.ejb3.tx.NullInterceptor.invoke(NullInterceptor.java:42)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
      at org.jboss.ejb3.security.Ejb3AuthenticationInterceptorv2.invoke(Ejb3AuthenticationInterceptorv2.java:186)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
      at org.jboss.ejb3.ENCPropagationInterceptor.invoke(ENCPropagationInterceptor.java:41)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
      at org.jboss.ejb3.BlockContainerShutdownInterceptor.invoke(BlockContainerShutdownInterceptor.java:67)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
      at org.jboss.aspects.currentinvocation.CurrentInvocationInterceptor.invoke(CurrentInvocationInterceptor.java:67)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
      at org.jboss.ejb3.stateless.StatelessContainer.dynamicInvoke(StatelessContainer.java:421)
      at org.jboss.ejb3.remoting.IsLocalInterceptor.invokeLocal(IsLocalInterceptor.java:85)
      at org.jboss.ejb3.remoting.IsLocalInterceptor.invoke(IsLocalInterceptor.java:72)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
      at org.jboss.aspects.remoting.PojiProxy.invoke(PojiProxy.java:62)
      at $Proxy317.invoke(Unknown Source)
      at org.jboss.ejb3.proxy.impl.handler.session.SessionProxyInvocationHandlerBase.invoke(SessionProxyInvocationHandlerBase.java:207)
      at org.jboss.ejb3.proxy.impl.handler.session.SessionProxyInvocationHandlerBase.invoke(SessionProxyInvocationHandlerBase.java:164)
      at $Proxy320.validaLavoro(Unknown Source)
      at org.swimv2.servlet.CreaLavoroServlet.doPost(CreaLavoroServlet.java:100)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
      at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:235)
      at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
      at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:190)
      at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:92)
      at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.process(SecurityContextEstablishmentValve.java:126)
      at org.jboss.web.tomcat.security.SecurityContextEstablishmentValve.invoke(SecurityContextEstablishmentValve.java:70)
      at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
      at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
      at org.jboss.web.tomcat.service.jca.CachedConnectionValve.invoke(CachedConnectionValve.java:158)
      at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
      at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:330)
      at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:829)
      at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:598)
      at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
      at java.lang.Thread.run(Unknown Source)
  Caused by: javax.persistence.PersistenceException: org.hibernate.exception.GenericJDBCException: could not insert: [org.swimv2.model.Lavoro]
      at org.hibernate.ejb.AbstractEntityManagerImpl.throwPersistenceException(AbstractEntityManagerImpl.java:614)
      at org.hibernate.ejb.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:226)
      at org.jboss.jpa.tx.TransactionScopedEntityManager.persist(TransactionScopedEntityManager.java:187)
      at org.swimv2.controller.GestioneLavoro.validaLavoro(GestioneLavoro.java:81)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
      at java.lang.reflect.Method.invoke(Unknown Source)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeTarget(MethodInvocation.java:122)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:111)
      at org.jboss.ejb3.EJBContainerInvocationWrapper.invokeNext(EJBContainerInvocationWrapper.java:69)
      at org.jboss.ejb3.interceptors.aop.InterceptorSequencer.invoke(InterceptorSequencer.java:73)
      at org.jboss.ejb3.interceptors.aop.InterceptorSequencer.aroundInvoke(InterceptorSequencer.java:59)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
      at java.lang.reflect.Method.invoke(Unknown Source)
      at org.jboss.aop.advice.PerJoinpointAdvice.invoke(PerJoinpointAdvice.java:174)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
      at org.jboss.ejb3.interceptors.aop.InvocationContextInterceptor.fillMethod(InvocationContextInterceptor.java:72)
      at org.jboss.aop.advice.org.jboss.ejb3.interceptors.aop.InvocationContextInterceptor_z_fillMethod_1851190336.invoke(InvocationContextInterceptor_z_fillMethod_1851190336.java)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
      at org.jboss.ejb3.interceptors.aop.InvocationContextInterceptor.setup(InvocationContextInterceptor.java:88)
      at org.jboss.aop.advice.org.jboss.ejb3.interceptors.aop.InvocationContextInterceptor_z_setup_1851190336.invoke(InvocationContextInterceptor_z_setup_1851190336.java)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
      at org.jboss.ejb3.connectionmanager.CachedConnectionInterceptor.invoke(CachedConnectionInterceptor.java:62)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
      at org.jboss.ejb3.entity.TransactionScopedEntityManagerInterceptor.invoke(TransactionScopedEntityManagerInterceptor.java:56)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
      at org.jboss.ejb3.AllowedOperationsInterceptor.invoke(AllowedOperationsInterceptor.java:47)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
      at org.jboss.ejb3.tx.NullInterceptor.invoke(NullInterceptor.java:42)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
      at org.jboss.ejb3.stateless.StatelessInstanceInterceptor.invoke(StatelessInstanceInterceptor.java:68)
      at org.jboss.aop.joinpoint.MethodInvocation.invokeNext(MethodInvocation.java:102)
      at org.jboss.aspects.tx.TxPolicy.invokeInOurTx(TxPolicy.java:79)
      ... 46 more
  Caused by: org.hibernate.exception.GenericJDBCException: could not insert: [org.swimv2.model.Lavoro]
      at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:126)
      at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:114)
      at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
      at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:64)
      at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2186)
      at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2666)
      at org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:71)
      at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:279)
      at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:321)
      at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:204)
      at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:130)
      at org.hibernate.ejb.event.EJB3PersistEventListener.saveWithGeneratedId(EJB3PersistEventListener.java:49)
      at org.hibernate.event.def.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:154)
      at org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:110)
      at org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:61)
      at org.hibernate.impl.SessionImpl.firePersist(SessionImpl.java:645)
      at org.hibernate.impl.SessionImpl.persist(SessionImpl.java:619)
      at org.hibernate.impl.SessionImpl.persist(SessionImpl.java:623)
      at org.hibernate.ejb.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:220)
      ... 80 more
  Caused by: java.sql.SQLException: Field 'ID' doesn't have a default value
      at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1074)
      at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4096)
      at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4028)
      at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2490)
      at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2651)
      at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2734)
      at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2155)
      at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2458)
      at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2375)
      at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2359)
      at org.jboss.resource.adapter.jdbc.WrappedPreparedStatement.executeUpdate(WrappedPreparedStatement.java:365)
      at org.hibernate.id.IdentityGenerator$GetGeneratedKeysDelegate.executeAndExtract(IdentityGenerator.java:94)
      at org.hibernate.id.insert.AbstractReturningDelegate.performInsert(AbstractReturningDelegate.java:57)
      ... 95 more
  </code></pre>
  
  <p>Actual entity code for the interesting part:</p>
  
  <pre><code>@Entity
  public class Lavoro implements Serializable {
      private static final long serialVersionUID = 1L;
  
  
      @Id
      @GeneratedValue(strategy = GenerationType.AUTO)
      private long id;
  
      private String nome;
  
      private String sede;
  
      private String stato;
  </code></pre>
  
  <p>Code in which I encounter the error:</p>
  
  <pre><code>Lavoro lavoro = new Lavoro();
          lavoro.setNome(formLavoro.getNome());
          lavoro.setSede(formLavoro.getSede());
          lavoro.setStato("PENDENTE");
          lavoro.setPersona(p);
          lavoro.setAbilitas(listaAbilita);
          lavoro.setRichiestapartecipazionelavoros(new ArrayList&lt;Richiestapartecipazionelavoro&gt;());
          lavoro.setPersonas(new ArrayList&lt;Persona&gt;());
          lavoro.setFeedbacks(new ArrayList&lt;Feedback&gt;());
          System.out.println("Prima del persist");
          manager.persist(lavoro);
  </code></pre>
  
  <p>NB:manager is the entity manager.</p>
  
  <p>MySQL for the ID field is set to <code>NOT_NULL</code> and <code>AUTO_INCREMENT</code>.</p>