The PropertyResourceBundle class constructor takes an InputStream (not a Reader). Does this mean that the property files that back the PropertyResourceBundle always have to be encoded in ASCII (Cp1252 really on windows)? How are people (localizers) dealing with that in Japan/Korea/China etc.?

According to the book Core Java 1.1, Advanced Features, this is the case. The work around suggested in the book is to use ListResourceBundle instead.

According to Sun's Bug Parade, there is a work around, of sorts. The property files (at least as of 1.2) will support unicode characters if they are placed in the property file using the uXXXX notation. Not very nice.

The RFE number is 4221013

This is listed as a request for enhancement, but acting on it will be limited, based on the comments from Sun about concerns over backwards compatibility.