Could not fetch initial value

<!DOCTYPE hibernate-mapping PUBLIC 
"-//Hibernate/Hibernate Configuration DTD 3.0//EN" 
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>

<class name="dot.modelo.cartao" table="cartao">

<id name="id">
        <generator class="increment"/>
</id>

<property name="dia" column="dia"/>
<property name="entrada" column="entrada"/>
<property name="retInt" column="retint"/>
<property name="saida" column="saida"/>
<property name="th" column="th"/>

</class>
</hibernate-mapping>

Hibernate: /*insert dot.modelo.doxo*/insert into doxo (doxo, lol, id) values (?, ?, ?)
Exception in thread "main" org.hibernate.exception.GenericJDBCException: could not insert: [dot.modelo.doxo]
    at org.hibernate.exception.ErrorCodeConverter.handledNonSpecificException(ErrorCodeConverter.java:92)
    at org.hibernate.exception.ErrorCodeConverter.convert(ErrorCodeConverter.java:80)
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
    at org.hibernate.persister.entity.BasicEntityPersister.insert(BasicEntityPersister.java:1839)
    at org.hibernate.persister.entity.BasicEntityPersister.insert(BasicEntityPersister.java:2171)
    at org.hibernate.action.EntityInsertAction.execute(EntityInsertAction.java:46)
    at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:239)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:223)
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:136)
    at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:274)
    at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27)
    at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:669)
    at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:293)
    at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:86)
    at dot.Main.main(Main.java:70)
Caused by: java.sql.SQLException: An SQLException was provoked by the following failure: java.lang.NullPointerException
    at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:68)
    at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:57)
    at com.mchange.v2.c3p0.stmt.GooGooStatementCache$2.run(GooGooStatementCache.java:343)
    at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:354)
Caused by: java.lang.NullPointerException
    at com.mysql.jdbc.PreparedStatement.asSql(PreparedStatement.java:562)
    at com.mysql.jdbc.PreparedStatement.asSql(PreparedStatement.java:504)
    at com.mysql.jdbc.PreparedStatement.toString(PreparedStatement.java:3228)
    at java.lang.String.valueOf(String.java:2577)
    at java.lang.StringBuffer.append(StringBuffer.java:220)
    at com.mysql.jdbc.trace.Tracer.printParameters(Tracer.aj:240)
    at com.mysql.jdbc.trace.Tracer.printEntering(Tracer.aj:167)
    at com.mysql.jdbc.trace.Tracer.entry(Tracer.aj:126)
    at com.mysql.jdbc.trace.Tracer.ajc$before$com_mysql_jdbc_trace_Tracer$1$f51c62b8(Tracer.aj:45)
    at com.mysql.jdbc.Connection.registerStatement(Connection.java)
    at com.mysql.jdbc.Statement.<init>(Statement.java:190)
    at com.mysql.jdbc.PreparedStatement.<init>(PreparedStatement.java:429)
    at com.mysql.jdbc.Connection.clientPrepareStatement(Connection.java:2063)
    at com.mysql.jdbc.Connection.clientPrepareStatement(Connection.java:1996)
    at com.mysql.jdbc.Connection.prepareStatement(Connection.java:4266)
    at com.mysql.jdbc.Connection.prepareStatement(Connection.java:4185)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:585)
    at com.mchange.v2.c3p0.stmt.GooGooStatementCache$2.run(GooGooStatementCache.java:333)
    ... 1 more

Session sessao = HibernateUtility.getSession();
        Transaction transaction = sessao.beginTransaction();
               
        doxo d = new doxo();  
        d.setDoxo("doOOXOXO");
        d.setLol("lOOOOLll");


        sessao.save(d);
        
        transaction.commit();
        sessao.close();

76        session.flush();
77        tx.commit();
78        session.close();

protected void commit(Session sess, Transaction tx) throws Exception {

logF.debug("#################### Entrou no evento commit");
		
Exception exc = new Exception();
String msg = "";
		
try {

sess.flush();
  if ( tx != null ) {
          tx.commit();       
         aposChamarBO(sess); 
			  }
       logF.debug("############# Commit ok");
       if (logTempoTransacao.isDebugEnabled()) 
	logTempoTransacao.debug("Fez commit em "+ new java.util.Date());		
			
	} catch (JDBCException e1) {
			log.fatal("Erro SQL ao tentar gravar: " + e1);
			msg="erros.sql.geral";
			exc = e1;
		} catch (HibernateException e2) {
			log.fatal("Erro Hibernate ao tentar gravar: " + e2);
	exc = e2;
			msg="erros.hibernate.geral";
		} catch (Exception e) {
			log.error("Erro Geral ao tentar gravar: " +e,e);
			e.printStackTrace();
			exc = e;
			msg="erros.persistencia.geral";
		} 

		try {
				
	       // Setando o autoCommit para falso devido a erro com o mysql
	       // se a transacao for nula entao considera que o objeto esta sendo
	       // com CMP
	      if (tx!=null) 
	      	  sess.connection().setAutoCommit(false);
			
		  if (tx!=null) tx.rollback();
		
		    Connection con = sess.close();
			
// Muda autocommit para true para atender ao websphere
// TODO Precisa ser homologado com demais App Servers
			con.setAutoCommit(true);
			con.close();
			
logF.debug("############# Fechou e devolveu conexao para o pool");

 } catch (Exception ex) {
  log.fatal("Nao conseguiu devolver o pool para o App Server:"+ex);
	msg="erros.persistencia.geral";
			exc=ex;
		}	
	
	if (!msg.equals("")) {
			MsgErro erro = MsgErro.getInstance();
			throw erro.msg(msg,new Object[] {exc},exc);
		}

		if (logTempoTransacao.isDebugEnabled()) 
			logTempoTransacao.debug("Encerrou Classe:"+this.getClass()+" com commit em Tempo:");
		
	}

Session sess = new HibernateUtil.getSession();
Transaction tx = sessi.beginTransaction();

doxo d = new doxo();

d.setDoxo("lOLLL");
d.setLol("DoxoOO");
d.setId(1);

sess.save(d);

tx.commit();
sess.close();