cnc study 01

import java.awt.Canvas;import java.awt.Color;import java.awt.FlowLayout;import java.awt.Graphics; import javax.swing.JFrame; public class Fortress extends JFrame {   /**   * default serial id   */  private static final long serialVersionUID = -7065629910752205393L;   private FortressCanvas canvas= null;  public Fortress()  {    initalize();     }   /**   * 어플리케이션 초기화   */  private void initalize() {    setSize(300, 300);    setLocation(300, 300);    System.out.println("layout name : " + getLayout().getClass().getName());       canvas= new FortressCanvas();    canvas.setSize(200, 200);    canvas.setBackground(Color.BLACK);       setLayout(new FlowLayout());    add(canvas);  }   public static void main(String[] args)  {    Fortress app= new Fortress();    app.run();  }   /**   * 어플리케이션을 수행 합니다.   */  private void run() {    setVisible(true);  }   class FortressCanvas extends Canvas {       public FortressCanvas()    {      initalize_canvas();    }       private void initalize_canvas() {      setForeground(Color.WHITE);    }     public void paint(Graphics g)    {      g.drawString("Hello nnc", 20, 100);           g.setColor(Color.RED);      g.drawRect(100, 100, 20, 20);           g.setColor(Color.BLUE);      g.drawRect(130, 100, 40, 40);    }  }}