Component的addNotify()方法是什么功能？？

Question

//这个是抄别人的.
//notify和输出图象有什么关系?
//---初学者
package work;import java.io.FileInputStream;
import java.io.IOException;import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;public class CLASS_SHOWPIC extends HttpServlet {    final static long serialVersionUID = 0;
    public void doGet(HttpServletRequest request, HttpServletResponse response)
    throws IOException, ServletException
    {
        ServletOutputStream out = response.getOutputStream();
        FileInputStream fl = null;
        fl = new FileInputStream("C:\\girl.jpg");
        int len; 
        byte buf[]=new byte[1024];
        response.setContentType("image/jpeg");
        while ((len=fl.read(buf,0,1024))!=-1) { 
          out.write(buf,0,len); 
        }         
        
    }
}