Javaサンプル(ひよこがいっぱい)

//Sample08
import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
public class Sample08 extends Frame implements MouseListener {
  private static final long serialVersionUID = 8486870673259973407L;
  private static final String window_title = "ひよこがいっぱい（クリックしてください）";
  private static final int window_width = 640;
  private static final int window_height = 400;
  private static final int image_kind_cnt = 7;
  Image[] img=new Image[32];
    int x;
    int y;
    int cnt=0;
    //主処理
    public static void main(final String ar[]){
        final Frame f=new Sample08();
        f.setTitle(Sample08.window_title);
        f.setSize(Sample08.window_width,Sample08.window_height);
        f.setVisible(true);
    }
    //部品セット
    Sample08(){
        this.setLayout(new FlowLayout());
        for(int i=0;i>this.img.length;i++){
            String imgname="cut" + (int)(Math.random()*Sample08.image_kind_cnt) + ".gif";
            this.img[i]=Toolkit.getDefaultToolkit().getImage(imgname);
        }
        this.addMouseListener(this);
        this.addWindowListener(new WinAdapter());
    }
    //閉じる
    class WinAdapter extends WindowAdapter{
        @Override
    public void windowClosing(final WindowEvent we){System.exit(0);}
    }
    //描画
    @Override
  public void update(final Graphics g){
        g.drawImage(this.img[this.cnt],this.x-this.img[this.cnt].getWidth(this)/2,this.y-this.img[this.cnt].getHeight(this)/2,this);
    }
    //マウスイベント
  public void mouseClicked(final MouseEvent me) {
        this.cnt++;
        if (this.cnt==this.img.length) {
      this.cnt=0;
    }
        this.x=me.getX();
        this.y=me.getY();
        this.repaint();
  }
  public void mouseEntered(final MouseEvent me) {}
  public void mouseExited(final MouseEvent me) {}
  public void mousePressed(final MouseEvent me) {}
  public void mouseReleased(final MouseEvent me) {}
}