import java.awt.*; import javax.swing.JFrame; import javax.swing.SwingUtilities; public class PaintClass { public PaintClass() { JFrame frame = new JFrame("Linie zeichnen") { public void paint(Graphics g) { g.drawLine(50, 50, 200, 200); } }; frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setSize(400, 400); frame.setLocationRelativeTo(null); frame.setVisible(true); } public static void main(String[] args) { SwingUtilities.invokeLater(() -> new PaintClass()); } }