I have an applet (java) that writes some files to the client file system. In Chrome and IE work perfectly and firefox too, only if I run it with Administrator permissions . (righ click -> Run as administrator). This solution don’t look proper for a enterprise application.
By the way the applet is part of a big enterprise web application. So I don’t have the security that the clients will be able to run firefox as administrator.
A good place to store application data is in a sub-directory of user.home. Use a sub-directory based on the package name of the main class, to help avoid your ‘settings.dat’ colliding with our ‘settings.dat’!
To make it even more ‘Windows friendly’ (when the relevant property indicates Win. of course!) the root directory for settings for any Java app. might be ${user.home}/AppData/Local/Java/