import java.awt.*;
import javax.swing.*;

public class Spreadsheet
{
  public static void main(String[] args)
  {
    final int N = 20;
    JFrame frame = new JFrame("Spreadsheet");
    frame.setSize(300,300);
    JPanel sheet = new JPanel();
    JScrollPane jsp = new JScrollPane(sheet);
    sheet.setLayout(new GridLayout(N, 1));
    for (int i=0; i<N; i++)
      {
        JPanel row = new JPanel();
        for (int j=0; j<N; j++)
          {
            JTextField cell = new JTextField(5);
            if (j % 2 == 1)
              cell.setBackground(Color.gray);
            row.add(cell);
          }
        sheet.add(row);
      }
    JPanel header = new JPanel();
    for (int i=0; i<N; i++)
      {
        JTextField title = new JTextField(5);
        title.setText(String.valueOf((char) ('A' + i)));
        title.setEditable(false);
        header.add(title);      
      }
    jsp.setColumnHeaderView(header);
    frame.getContentPane().add(jsp);
    frame.setVisible(true);
  }
}