use servlet to generate image for large amount of request

[autogoor]

Let's think about maps.yahoo.com. I do not know how they handle
millions of request and generate the map pictures quickly. If I use a
servlet, in the post or get method I use:

BufferedImage mapImage = myTookKit.generateMap(String address);
response.setContentType("image/png");
OutputStream os = response.getOutputStream();
ImageIO.write(buffer, "png", os);
os.close();

Is servlet a good choice? If I use servlet, is the code above good
enough to handle hundreds of request? Is the choice of BufferedImage a
good one? What special technique I need to implement "myTookKit" to
make it faster? I am thinking about JNI.

Thanks,