JTable add instead of update

Hi, I am using a JTable, with two vectors, I am not using TableModel,
just using JTable table = new Jtable(Vector data, Vector column),but now when
I apdate, the new rows are added, this is not what I want, I want only the new data show in the table.

final JTable jt = new JTable(data,headers);
JScrollPane jsp = new JScrollPane(jt);
getContentPane().add(BorderLayout.NORTH,jsp);
getContentPane().add(BorderLayout.SOUTH,panel);



I have another question please I put the table in a scrollPane, but the scrollPane does not appear.
Your help will be appreciate.
Thanks