BIRT itself is a stand alone application (albeit and eclipse applciation not a swing app).
You should have no issues using BIRT to produce static reports and including those in your swing app, since these are just gif, pdfs, jpegs etc. However, dynamic reports rely on JavaScript to implement their interactive behaviour so integrating these might be trickier. I'm not sure this is possible, but you could try reusing BIRT own viewer stuff?