Nokia is a very popular smart phone which run on S40 java OS and s60 Symbian OS .
Nokia has million of themes, software, games etc. So the developers make it as much as they can .
Now you can change folder icon of your Nokia java mobile.This trick only works in Nokia S40 (java) phones.
Go to any folder and Rename that folder with .nth e.g., If i want to change my folder i.e. Vishal then I will rename it Vishal.nth