javac doesn't work in some locales, including ja, ko, zh_TW, etc.  The error is:

% uname
SunOS
% env LANG=ja /usr/local/java/jdk1.4/solsparc/bin/javac -verison
Exception in thread "main" java.lang.NoClassDefFoundError: com/sun/tools/javac/Main
% env LANG=ko /usr/local/java/jdk1.4/solsparc/bin/javac -verison
Exception in thread "main" java.lang.NoClassDefFoundError: com/sun/tools/javac/Main

% uname
Linux
% env LANG=ja /usr/local/java/jdk1.4/linux-i386/bin/javac -version
javac: invalid flag: -version
Usage: javac <options> <source files>
where possible options include:
  -g                        Generate all debugging info
  -g:none                   Generate no debugging info
  -g:{lines,vars,source}    Generate only some debugging info
  -O                        Optimize; may hinder debugging or enlarge class file
  -nowarn                   Generate no warnings
  -verbose                  Output messages about what the compiler is doing
  -deprecation              Output source locations where deprecated APIs are used
  -classpath <path>         Specify where to find user class files
  -sourcepath <path>        Specify where to find input source files
  -bootclasspath <path>     Override location of bootstrap class files
  -extdirs <dirs>           Override location of installed extensions
  -d <directory>            Specify where to place generated class files
  -encoding <encoding>      Specify character encoding used by source files
  -source <release>         Provide source compatibility with specified release
  -target <release>         Generate class files for specific VM version
  -help                     Print a synopsis of standard options

% env LANG=ja_JP.eucJP /usr/local/java/jdk1.4/linux-i386/bin/javac -version
Exception in thread "main" java.lang.NoClassDefFoundError: com/sun/tools/javac/Main

It doesn't work on Windows 2000 with setting ja locale.

See Comments for more information.