private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
 
        // import javax.swing.table.*;
 
        String [] [] data =
        {
                {"abc", null,  null, null},
                {null,  "def", null, null},
                {null,  null,  null, null},
                {null,  null,  null, null}
        };
 
        String [] title = { "A", "B", "C", "D" };
 
        DefaultTableModel model = new DefaultTableModel (data, title);
 
        jTable1.setModel(model);
 
        double [] [] cisla  = { { 10, 20 },
                                 {100, 200} };
        display (cisla);
    }                                        
 
    private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        double v = get (0, 1);
        jSpinner1.setValue(v);
        jSlider1.setValue ((int) v);
    }                                        
 
    private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // import java.lang.reflect.*;
        Object obj = this;
        Class cls = obj.getClass ();
        Method [] m = cls.getMethods();
 
        String [] [] data = new String [m.length][2];
        String [] title = { "name", "value" };
 
        for (int i = 0; i < m.length; i++)
        {
            data [i][0] = m[i].toString();
            if (m[i].getName().startsWith("get"))
                    {
                        try
                        {
                           data [i][1] = "" + m[i].invoke (obj, new Object [] {});
                        }
                        catch (Exception ex)
                        {
 
                        }
                    }
        }
 
        DefaultTableModel model = new DefaultTableModel (data, title);
        jTable2.setModel(model);
    }                                        
 
    public double get (int i, int j)
    {
        TableModel model = jTable1.getModel();
        Object value = model.getValueAt(i, j);
        double result = 0;
        if (value != null)
        {
           String s = (String) value;
           try
           {
              result = Double.valueOf (s);
           }
           catch (NumberFormatException ex)
           {
               result = -1;
           }
        }
        return result;
 
    }
 
    public void display (double [] [] a)
    {
        int lines = a.length;
        int columns = 0;
        for (int i = 0; i < lines; i++)
            if (a[i].length > columns)
                  columns = a[i].length;
 
        String [] [] data = new String [lines][columns];
 
        for (int i = 0; i < lines; i++)
            for (int j = 0; j < a[i].length; j ++)
                data [i][j] = "" + a[i][j];
 
        String [] title = new String [columns];
        for (int j = 0; j < columns; j++)
            title [j] = "" + (char) ('A' + j);
 
        DefaultTableModel model = new DefaultTableModel (data, title);
        jTable1.setModel(model);
    }