import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.*;

import javax.imageio.ImageIO;
import javax.servlet.*;
import javax.servlet.http.*;

import static java.awt.Color.*;

public class ConcentricCirc extends HttpServlet {
  private static final int width=200, height=200;
  
  @Override
  public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
    paint(img.createGraphics());
    
    response.setContentType("image/png");
    OutputStream out = response.getOutputStream();
    ImageIO.write(img, "png", out);
    out.close();
  }
  
  private static final Color[] cs = {red, yellow, green, cyan, blue, magenta};
  
  private void paint(Graphics2D g) {
    g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    g.setBackground(WHITE);
    g.clearRect(0, 0, width, height);
    int i;
    for (i=10; i>0; i--) {
      g.setColor(cs[i%cs.length]);
      g.fillOval(100-10*i, 100-10*i, 20*i, 20*i);
    }
  }
}