import java.awt.Graphics;
import javax.swing.JComponent;
import javax.swing.JFrame;
class MyCanvas extends JComponent {
public void paint(Graphics g) {
int[] x = new int[]{100,200,300,400};
int[] y = new int[]{400,300,300,100};
g.drawPolygon (x, y, x.length);
}
}
public class DrawPolygon {
public static void main(String[] a) {
JFrame window = new JFrame();
window.setBounds(30, 30, 300, 300);
window.getContentPane().add(new MyCanvas());
window.setVisible(true);
}
}