import javax.swing.JFrame;
import javax.swing.SwingUtilities;

public class Frame extends JFrame {
        private static final long serialVersionUID = -1;

        public Frame() {
                super("SampleFrame");
                getContentPane().add(new DrawPanel());
                setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                setSize(400, 300);
        }

        public static void main(String[] args) {
                SwingUtilities.invokeLater(new Runnable() {
                        @Override
                        public void run() {
                                Frame frame = new Frame();
                                frame.setVisible(true);
                        }
                });
        }
}