There is a bug in Java 6u13 and 6u14. https://bugs.java.com/bugdatabase/view_bug?bug_id=6835450
Simply put, the following code is supposed to open a browser window, but because of a bug in the framework, it stopped working in Java 1.6 update 13. Nothing opens anymore. There was a similar bug for Java applets (that was fixed in update 14), but this one still exists in update 14 for Java WebStart/JNLP.
getAppletContext().showDocument(new URL("http://www.sun.com"),"_blank");
Do you know of any workarounds?
I've not tried it in JNLP, but normally this should work:
java.awt.Desktop.getDesktop().browse(new URI("http://www.sun.com"));