Thread: java SQL problem

Connection connection = null;
        try {
            connection = DriverManager.getConnection("jdbc:derby://localhost:1527/database","root","root");
            connection.setAutoCommit(false);
            PreparedStatement query = connection.prepareStatement("INSERT INTO table (number) VALUES (?)");
            query.setInt(1, 12);
            int temp = query.executeUpdate();
 
            Sytem.out.println(temp);
 
            ResultSet rs = query.getGeneratedKeys();
 
            while (rs.next()) {
                System.out.println(rs.getInt(1));
            }
 
            connection.commit();
        } catch (SQLException ex) {
            if(connection != null){
                try {
                    connection.rollback();
                } catch (SQLException ex1) {
                    Logger.getLogger("meh").log(Level.SEVERE, null, ex1);
                }
            }
            Logger.getLogger("meh").log(Level.SEVERE, null, ex);
        }finally{
            try {
                if(connection != null)
                    connection.close();
            } catch (SQLException ex) {
                Logger.getLogger("meh").log(Level.SEVERE, null, ex);
            }
        }

Why am I getting NullPointerException error on line with while? Data are inserted correctly I can check that but am still getting error on line with while.

Edit: Oh sure and data am trying to get should be id generated by DB.

getting NullPointerException error on line with while

while (rs.next()) {
What value does the rs variable have?

System.out.println(rs); is getting back null but by my opinion it should get back that id or am I wrong?

god am so dumb. Problem was in line PreparedStatement query = connection.prepareStatement("INSERT INTO table (number) VALUES (?)"); It should be connection.prepareStatement("INSERT INTO item (weight, storedays, dangerous) VALUES (?,?,?)",Statement.RETURN_GENERATED_KEYS); now I hate myself.