The first two questions refer to the following code segment: 

private static void buildTableModel(JTable table) {
     ResultSet rs = DroneDb.getResultSet("SELECT * from drones");
     try {
         ResultSetMetaData metaData = rs.getMetaData();
        Vector<String> columnNames = new Vector<String>();
        int columnCount = metaData.getColumnCount();
        for (int column = 1; column <= columnCount; column++) {
            columnNames.add(metaData.getColumnName(column));
        }

        // data of the table
        Vector<Vector<Object>> data = new Vector<Vector<Object>>();
        while (rs.next()) {
            Vector<Object> vector = new Vector<Object>();
            for (int columnIndex = 1; columnIndex <= columnCount; columnIndex++) {
                vector.add(rs.getObject(columnIndex));
            }
            data.add(vector);
        }
        table.setModel(new DefaultTableModel(data, columnNames));
     } catch (SQLException e) {
         e.printStackTrace();
     }
    }