I've used a very good library for this kind of things that can produce .png and .jpeg from a servlet and jsp, getting data with jdbc or with xml. You can check on www.sitraka.com site for the JClass ServerChart, it's possible to define the chart layout from JBuilder and then link it to a database via an URL. You can download a time-limited tryal version, to check if it meets your needs, but I believe it has all you can ask to plot charts.