Eclipse SWTChart
Eclipse SWTChart allows to create different types of charts. The API is well designed and allows to create Line, Bar and Scatter charts easily. Size, colors, axes, ranges and all aspects of the charts can be modified via code. So, it's easy to create customized charts. Moreover, the library already contains a data compression to show large data sets in a performant way. In addition to that, charts can be created even more easily with the SWTChart extensions.