issue with this tutorial:Populate a tableview using database in JavaFX

I get a nullpointerxception when following this tutorial: Populate a tableview using database in JavaFX .

I modified it to make it simpler and fit my needs: Instead of Usermaster, I have Person object.

 while(rs.next()){
        Person per = new Person();
        per.ClientID.set(rs.getInt(1));
        per.FirstName.set(rs.getString(2));
        per.LastName.set(rs.getString(3));

The code stops at per.ClientID.set(rs.getInt(1)); due to nullpointerxception.

If I make system.out.println(rs.getInt(1)) (or any other column), I get the value... But it appears that I can't pass it to my object per.

All Person object vars are SimpleString/IntergerProperty type, as shown in the tutorial.

Can someone help me to identify the mistake I made in coding this?

Thank you

**Update: need to initialize values.

now stuck with nullpointerexception here:

while(rs.next()){
        Person per = new Person();
        per.ClientID.set(rs.getInt("CLIENTID"));
        per.FirstName.set(rs.getString("FIRSTNAME"));
        per.LastName.set(rs.getString("LASTNAME"));

        data.add(per);  

    }
    tableview.setItems(data);  ---> here