public boolean ChangeReturnStatus(String id,int nn){           Connection conn=HibernateUtil.getSession().connection();            String sql = "update TableName set a='" + nn+ "' where TypeID='"+id+"'";              Statement stmt=null;         int i=0;         try {             stmt=conn.createStatement();              i= stmt.executeUpdate(sql);            if(i!=0){               return true;            }         } catch (Exception e) {             e.printStackTrace();         }         return false;     }