You can load the data from a different location for example and change it. Remember to reload it though.

String lines[] = loadStrings("http://www.yourserver.com/list.txt");

but keep in mind that you might have to sign the applet depending on where this file is located. 
http://wiki.processing.org/index.php/Sign_an_Applet?id=hacks:signapplet

You might also find sketchpath(String) useful.  It prepends the path to the sketch folder to the string parameter being passed and returns this as a string.  This is probably more useful in standalone applications rather than applets (where you usually know where they're being uploaded and so can hard-code a URL) but thought it was worth a mention.  I've used it in a standalone application that requires user-data to be added.

IIRC there is also a dataPath() method; though that's obviously not what you're after ;)

Hi!
I have a similar problem.
I'm using

loadStrings("http://my_web_path/data.txt");

code to read data from txt file and show them in applet.

When applet is running on serwer, it reads data from file properly. But when I change data in text file, applet shows old unchanged data from this file.

When I run it as application (File->Export Application) from my computer it works fine and refreshes data from Web.
When I run it with Run from inside Processing it works fine as well.
But when I run it as applet from my computer it have the same problems refreshing data as when runnig on server.

Could someone possibly help me with this problem?
Thanks for response
misiopysio

Strange, I don't think it should cache data like this. Browsers do cache data from Web pages, Java caches the jar files (so you have to clear the cache when you update the jars) but a PApplet should always get fresh data. Unless you have a proxy doing the cache?
There is a trick to avoid such cache: append ? followed by a random number to the URL, something like loadStrings("http://my_web_path/data.txt?" + System.currentTimeMillis());