When I need to start a Java webstart app, I usually do it from command line, instead of using a browser. There are 2 slightly different ways to do that:
javaws with the url to the jnlp file:
%JAVA_HOME%\bin\javaws http://www.foo123.com/bar/buz.jnlp2. Save the jnlp file locally and run
javawscommand with the local copy. If you enter this jnlp url in the browser's address bar, it will run the app instead of downloading the file. So here I use
wgetto download the file.
cd %HOMEPATH%\DesktopOption 2 is a bit faster since it doesn't retrieve the jnlp file every time, and can still work even in case of network problem. But the downside is you may not get the latest version of the application. This auto-update is supposed to be the main benefit of jnlp. If your applications don't update frequently, or you don't care running an obsolete version, option 2 is fine.
To make the command shorter, I created a batch file
rem %JAVA_HOME%\bin\javaws http://www.foo123.com/bar/buz.jnlp