Java tutorial
import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Shape; import java.awt.geom.Rectangle2D; import javax.swing.JFrame; import javax.swing.JPanel; public class Main extends JPanel { public void paint(Graphics g) { Shape shape = new Rectangle2D.Float(100, 50, 80, 80); Graphics2D g2 = (Graphics2D) g; g2.fill(shape); } public static void main(String[] args) { JFrame frame = new JFrame(); frame.add(new Main()); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setBounds(20, 20, 500, 500); frame.setVisible(true); } }