public   boolean  UpdateUserAccount( int   editid,
                                     String firstname,
                                     String lastname,
                                     String nickname){
       boolean  return_udp_Value = false;
      Connection connection =  null ;
       try {
        connection = DriverManager.getConnection(dbUrl, dbUserName, dbPassword);
        connection.setAutoCommit(false);
        String sql = "UPDATE Users SET FirstName=?, LastName=?, NickName=?, 
        WHERE Id=?";
        // Вот так пишутся prepared statements
        PreparedStatement s = connection.prepareStatement(sql);
        s.setString( 1 , firstname);
        s.setString( 1 , lastname);
        s.setString( 1 , nickname);
        s.setInt( 1 , editid);
        s.executeUpdate(sql);
        s.close();
        connection.commit();
        connection.close();
        return_udp_Value = true;
      }
       catch (SQLException e){
          ex.printStackTrace();
           try {
              connection.rollback();
              connection.close();
          } catch (SQLException se){}
        }

         return  return_udp_Value;
    }

ex.printStackTrace();