ds = (DataSource)ic.lookup("java:/DefaultDS");
   public void start() throws Exception   {      log.debug("starting JDBCPersistenceManager");      initSqlProperties();      InitialContext ic = new InitialContext();      mgr = (TransactionManager)ic.lookup("java:/TransactionManager");      ds = (DataSource)ic.lookup("java:/DefaultDS");      ic.close();      if (createTablesOnStartup)      {         createSchema();      }   }