There is a bug in Java 6u13 and 6u14. 
<http://bugs.sun.com/view_bug.do?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?