Problem z gui - zarządzanie rekordami

ClientTools ct = new ClientTools(conn);
    		java.util.List clients = ct.getClients();
    		Object[][] data = new Object[clients.size()][4];
    		for(int i = 0; i < clients.size(); i++) {
    			Client client = (Client)clients.get(i);
    			System.out.println(client.getName());
    			data[i][0] = client.getUid();
    			data[i][1] = client.getName();
    			data[i][2] = client.getSurname();
    			data[i][3] = client.getTel();
    			
    		}

Object[][] data

public class Dummy {
	private int i;
	private String s;
	
	public Dummy(String s, int i) {
		this.s = s;
		this.i = i;		
	}
	
	public void setS(String s) {
		this.s = s;
	}
	public String getS() {
		return s;
	}
	public void setI(int i) {
		this.i = i;
	}
	public int getI() {
		return i;
	}
}

import java.util.ArrayList;
import java.util.List;

import javax.swing.table.AbstractTableModel;


public class MyTableModel extends AbstractTableModel {
	
	List<Dummy> list;
	
	public MyTableModel() {
		list = new ArrayList<Dummy>();
		// zainicjowanie jakimis danymi
		list.add(new Dummy("A", 1));
		list.add(new Dummy("B", 2));
		list.add(new Dummy("C", 3));
		list.add(new Dummy("D", 4));
	}
	
	@Override
	public int getColumnCount() {
		return 3; //beda 3 kolumy: 2 na pola z Dummy oraz na przycisk
	}

	@Override
	public int getRowCount() {
		return list.size();
	}

	@Override
	public Object getValueAt(int x, int y) {
		switch (y) {
		case 0:
			return list.get(x).getS();
		case 1:
			return list.get(x).getI();
		default:
			return null;
		}
		
	}
}

import java.awt.Color;
import java.awt.Component;

import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JTable;
import javax.swing.table.DefaultTableCellRenderer;


public class MyCellRenderer extends DefaultTableCellRenderer  {
	
	JButton button = new JButton("Press");	
	
	@Override
	public Component getTableCellRendererComponent(JTable table, Object value,
			boolean isSelected, boolean hasFocus, int row, int column) {
		if (hasFocus) {
			setBorder(BorderFactory.createLineBorder(Color.YELLOW, 1));
		} else {
			setBorder(null);
		}
		switch (column) {
		case 0:
		case 1:
			setBackground(Color.LIGHT_GRAY);
			setText(value.toString());
			break;
		case 2:
			return button;
		}
		return this;
	}
}

import javax.swing.JFrame;
import javax.swing.JTable;
import javax.swing.table.TableCellRenderer;
import javax.swing.table.TableModel;


public class MainClass extends JFrame {
	
	public static void main(String[] args) {
		JFrame thisClass = new MainClass();
		
		TableCellRenderer cellRenderer = new MyCellRenderer();
		TableModel model = new MyTableModel();
		JTable table = new JTable(model);
		//ustawianie rendererow kolumn
		for (int i = 0; i < table.getColumnCount(); i++) {
			table.getColumnModel().getColumn(i).setCellRenderer(cellRenderer);
		}
		thisClass.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
		thisClass.add(table);
		thisClass.setSize(250, 120);
		thisClass.setVisible(true);
	}
}