15.1

import java.awt.Color;
import java.awt.Graphics;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class Test_15 extends JFrame{

public  Test_15(){
add(new JP());
}
public static void main(String[] args) {
// TODO Auto-generated method stub
Test_15 t = new Test_15();
t.setTitle("test");
t.setSize(200,200);
t.setLocationRelativeTo(null);
t.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
t.setVisible(true);
}

}

class JP extends JPanel{
protected void paintComponent(Graphics g){
super.paintComponent(g);

int width = getWidth();
int height = getHeight();
g.setColor(Color.BLUE);
g.drawLine(0, height/3, width, height/3);
g.drawLine(0, 2*height/3, width, 2*height/3);
g.setColor(Color.RED);
g.drawLine(width/3,0, width/3,height);
g.drawLine(2*width/3,0, 2*width/3,height);
}
}