Source is included and it's all extremely well documented. GraphReader An easy way to determine coordinates in scanned graphs. This applet reads a file which contains two lists of items which have one to one relationships. Example - States and Capitols. The JetChart Library is a set of java classes that displays a large variety of java charts from applets, java applications and servlets.
Source is included in the zip file.
NF4 Draws line graphs, bar charts, or pie charts according to user-defined parameters. PieChart A customizable pie chart generator. Just load your data into the parameter tags. The standard display and the The Japanese Candle Chart display. It has lots of options and you can read data from an external file, or even multiple files.