If you configured your jre correctly, then my unicode test class should display things more interesting than little empty squares. Except if you are on ms-windows, apparently. Then you may want to just use jdrill as your test program.
For the trivial class test, download unicode.class (src = unicode.java) and run with your equivalent of
jre -cp . unicodeYou will want to specifically look at the lines marked by 3040 - 30c0
I'd love to hear about any specifics that I have missed. Feel free to email me updated information.
If you're looking for a test for non-ascii fonts for your browser, try my JIS browser test page which tests the Japanese range of fonts for browsers.