If you try to start a Java webstart application like this:
$ javaws http://localhost:82/studio/Studio.jnlp
And get blocked by the Java security mechanism:
You'd normally have to go through the tedious process of locating the Java Control Panel, click on the security tab, click on the exception list icon, click "add a new URL", enter the URL, click ok, click "confirm I know what I'm doing" and finally close the bulky control application.
If you, like me, work with lots of java webstart apps from many sources that Java doesn't approve of, this becomes an irritation.
The command line to the rescue: You can solve it by simply adding the URL to the security exception list text file like this:
$ echo http://localhost:82 >> ~/.java/deployment/security/exception.sites
This is so faster than clicking through the Java Control Centre dialogues 😃