15.1

 1 import java.awt.Color;
 2 import java.awt.Graphics;
 3 
 4 import javax.swing.JFrame;
 5 import javax.swing.JPanel;
 6 
 7 public class Test_15 extends JFrame{
 8 
 9     public  Test_15(){
10         add(new JP());
11     }
12     public static void main(String[] args) {
13         // TODO Auto-generated method stub
14         Test_15 t = new Test_15();
15         t.setTitle("test");
16         t.setSize(200,200);
17         t.setLocationRelativeTo(null);
18         t.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
19         t.setVisible(true);
20     }
21 
22 }
23 
24 class JP extends JPanel{
25     protected void paintComponent(Graphics g){
26         super.paintComponent(g);
27         
28         int width = getWidth();
29         int height = getHeight();    
30         g.setColor(Color.BLUE);
31         g.drawLine(0, height/3, width, height/3);
32         g.drawLine(0, 2*height/3, width, 2*height/3);
33         g.setColor(Color.RED);
34         g.drawLine(width/3,0, width/3,height);
35         g.drawLine(2*width/3,0, 2*width/3,height);
36     }
37 }
Test_15