If you are using windows you can use rundll32
to launch a pdf file.
Try something like this
String pdfFile="D:/PDFChartStuff.pdf";
if (pdfFile.toString().endsWith(".pdf")) {
Runtime.getRuntime().exec("rundll32 url.dll,FileProtocolHandler " + pdfFile);
} else {
//For cross platform use
Desktop desktop = Desktop.getDesktop();
desktop.open(pdfFile);
}