The first issue to resolve is whether the user has the proper font installed on their system in order to display the specified unicode character.
You may have already tried to display various unicode characters, only to have a bunch of question marks displayed instead. The problem probably isn't the unicode specification, but that the necessary font isn't installed.
For example, if I were to try to display a simplified chinese character on my system, it wouldn't work as hoped because I don't have a simplified chinese font installed.
Try a quick search on Sun's
Java Tutorial for unicode and/or internationalization for more information.