Draw a Line on a JFrame in Java

The following is an example to draw a line on a JFrame −

Example

package my;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Line2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class SwingDemo extends JFrame {
   public SwingDemo() {
      JPanel panel = new JPanel();
      getContentPane().add(panel);
      setSize(550, 300);
   }
   public void paint(Graphics gp) { super.paint(gp); Graphics2D graphics = (Graphics2D) gp;
      Line2D line = new Line2D.Float(200, 150, 150, 220);
      graphics.draw(line);
   }
   public static void main(String[] args) {
      SwingDemo demo = new SwingDemo();
      demo.setVisible(true);
   }
}

Output