It's hard to say here without seeing more of the code you use to read or write the values you're talking about. However I suspect that at one or more points in your system you're using the wrong encoding. In general, anytime you're converting between raw bytes and chars,
you should probably be using one of these:
new InputStreamReader(InputStream in, String encoding)
new OutputStreamWriter(OutputStream out, String encoding)
new String(byte[] array, String encoding)
String.getBytes(String encoding)
(There are also various things in java.nio.charset.* which operate similarly.)
All these use the name of a charset as the encoding parameter. If you're not specifying the encoding, you're probably getting a default which is not what you want. If you don't know what encoding you're using, you need to find out. Are you getting input from a text file, or a database, or a socket steam, or what? Similarly, what are you writing to? Typically both input and output need to have a particular encoding (not necessarily the same), andyou need to find out what the expected encoding is. Or you can jsut experiment with changing the encoding value around; maybe you'll get lucky. Common choices for Japanese would probably be "shift-jis", "utf-16", or "utf-8". (There are a number of subtle variants on these, but chances are good that one of these three will be close enough to fix 99% of your problems, which is a good place to start at least.) Beware that there are generally a number of places throughout a system where there's translation between bytes and chars, and you may have to look at all of them. If encoding is screwed on during input, you can't usually fix it during output. Also it's possible the problem isn't with your Java program at all, but with whatever program you're using to look at the output with.
Sorry if this isn't more helpful. Try answering these questions:
Where did the data come from? What format was it in?
How exactly did it get converted to a String or char[] array in your Java program?
How does the data get output from your Java program?
How are you viewing the output?
Your problem could be anywhere within one of these step. Good luck.