Here's something different: it's very to embed web pages in SWT views. I recently tried it and it works very well. You can see where this is going: there are plenty of beautiful charting components for HTML, it could be an option. Just make sure the component is client-side only (unless you want to start a server).
I haven't tested Flash, but I'm pretty sure you can get it to work (naturally, this means your software will require Flash plug-in installed).