Simple.
Take that URL and Throw it against the Operating System.
the OS will use the default browser to open the link and show it to the user:
try {
Desktop desktop = java.awt.Desktop.getDesktop();
URI oURL = new URI("http://www.google.com");
desktop.browse(oURL);
} catch (Exception e) {
e.printStackTrace();
}
This is safe, cause it does not have any application reference to any browser or so - the OS decides. It's also a great way to deal with PDF files.