Java web - CAPTCHA

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package action;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import javax.servlet.http.*;
import javax.servlet.*;
import java.io.*;

/**
 *
 * @author 1
 */
public class Image extends HttpServlet {
    public static final String chars = "123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
    public static final String[] fonts = {"Arial","Calibri","Bernard MT Condensed","Algerian"};//,"Harlow Solid Italic" - nu ego nah
    /**
     * Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)  throws ServletException, IOException {
        BufferedImage image = new BufferedImage(200, 50, BufferedImage.TYPE_INT_RGB);
        Graphics2D graphics2D = image.createGraphics();
        int length = (int)(Math.random()*2+4);
        int lines = (int)(Math.random()*8+8);
        String capstr = "";
        // render to graphics 2d -
        // graphics2D.drawString(...), graphics2D.drawLine(...), etc.
        for(int i = 0; i < length; i++)
        {
            capstr += chars.charAt((int)(Math.random()*chars.length()));
        }//Font.getFont("Arial")
        //fonts[(int)(Math.random()*fonts.length)-1]
        graphics2D.setColor(Color.white);
        graphics2D.fillRect(0, 0, 200, 50);
        Font font = new Font(fonts[(int)(Math.random()*(fonts.length-1))], Font.BOLD, 24);
        graphics2D.setFont(font);
        graphics2D.setColor(Color.black);
        graphics2D.drawString(capstr, (int)(Math.random()*80+40), (int)(Math.random()*30+22));
        for(int i = 0; i < lines; i++)
        {
            graphics2D.drawLine((int)(Math.random()*200), (int)(Math.random()*50), (int)(Math.random()*200), (int)(Math.random()*50));
        }
        graphics2D.dispose();

        response.setContentType("image/jpeg");
        OutputStream outputStream = response.getOutputStream();
        ImageIO.write(image, "jpeg", outputStream);
        outputStream.close();
        request.getSession().setAttribute("captchaval", capstr);
    }
    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /**
     * Handles the HTTP <code>GET</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     * @throws ServletException if a servlet-specific error occurs
     * @throws IOException if an I/O error occurs
     */
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    /**
     * Returns a short description of the servlet.
     * @return a String containing servlet description
     */
    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>
}