How to dynamically change model data when changing value from the list that fills it?

You simply update the defaultTableModel that it will generate the events needed to update the JTable.

A simple solution to automate this procedure is to only use DefaultTableModel to save the data instead of List ... (gambiarra?)

Probably better, more flexible, especially if the application is not very simple, is to create (extend) a list that also implements TableModel . Here is a very simplified example:

public class MinhaLista {

    private final List<String> lista = new ArrayList<>();
    private final Modelo modelo = new Modelo();


    public TableModel getTableModel() {
        return modelo;
    }

    public int size() {
        return lista.size();
    }

    public String get(int index) {
        return lista.get(index);
    }

    public boolean contains(Object o) {
        return lista.contains(o);
    }

    public boolean add(String e) {
        boolean added = lista.add(e);
        if (added) {
            int row = lista.size()-1;
            modelo.fireTableRowsInserted(row, row);
        }
        return added;
    }

    public String remove(int index) {
        String removed = lista.remove(index);
        modelo.fireTableRowsDeleted(index, index);
        return removed;
    }

    public void clear() {
        lista.clear();
        modelo.fireTableDataChanged();
    }

    public MinhaLista() {
    }

    private class Modelo extends AbstractTableModel {

        @Override
        public Class<?> getColumnClass(int columnIndex) {
            if (columnIndex != 0)
                throw new IndexOutOfBoundsException("column: " + columnIndex);
            return String.class;
        }

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

        @Override
        public int getColumnCount() {
            return 1;
        }

        @Override
        public Object getValueAt(int row, int column) {
            if (column != 0)
                throw new IndexOutOfBoundsException("column: " + column);
            return lista.get(row);
        }
    }
}

Used as in:

public class TestMinhaLista {

    private static final MinhaLista lista = new MinhaLista();
    private static final JTextField status = new JTextField();

    public static void main(String[] args) {
        JTable table = new JTable(lista.getTableModel());

        JButton add = new JButton("add");
        add.addActionListener(TestMinhaLista::add);
        JButton remove = new JButton("remove");
        remove.addActionListener(TestMinhaLista::remove);
        JButton clear = new JButton("clear");
        clear.addActionListener(TestMinhaLista::clear);
        JPanel panel = new JPanel();
        panel.add(add);
        panel.add(remove);
        panel.add(clear);

        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(frame.DISPOSE_ON_CLOSE);
        frame.add(panel, BorderLayout.PAGE_START);
        frame.add(new JScrollPane(table), BorderLayout.CENTER);
        frame.add(status, BorderLayout.PAGE_END);
        frame.setSize(400, 400);
        frame.validate();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    private static void add(ActionEvent ev) {
        int num = lista.size() + 1;
        lista.add("linha " + num);
        status.setText("linha " + num + " adicionada");
    }

    private static void remove(ActionEvent ev) {
        if (lista.size() > 0) {
            int index = (int) (Math.random() * lista.size());
            String texto = lista.remove(index);
            status.setText("linha " + (index+1) + " removida: " + texto);
        } else {
            status.setText("nada para apagar");
        }
    }
    private static void clear(ActionEvent ev) {
        lista.clear();
        status.setText("lista serada");
    }
}

(I used delegation instead of extending the ArrayList because I'd rather have to implement the required methods rather than the risk of forgetting one of the methods)