Scala, Mac and -Dfile.encoding=UTF-8

Today, I noticed that my Scala can't print any Japanese characters on my MacBook.

% sbt
[info] Set current project to default-7cb4b4 (in build file:/Users/kzys/hello/)
> console
[info] Starting scala interpreter...
[info]
Welcome to Scala version 2.9.1.final (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_29).
Type in expressions to have them evaluated.
Type :help for more information.

scala> println("\u3041")
��

scala>

Actually, It caused from Java, not Scala, not sbt. You must pass -Dfile.encoding=UTF-8 to java(1). But how?

I find a good answer on Stack Overflow.

Since the command-line cannot always be accessed or modified, for example in embedded VMs or simply VMs launched deep within scripts, a JAVA_TOOL_OPTIONS variable is provided so that agents may be launched in these cases.

% JAVA_TOOL_OPTIONS='-Dfile.encoding=UTF8' sbt
Picked up JAVA_TOOL_OPTIONS: -Dfile.encoding=UTF8
[info] Set current project to default-7cb4b4 (in build file:/Users/kzys/hello/)
> console
[info] Starting scala interpreter...
[info]
Welcome to Scala version 2.9.1.final (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_29).
Type in expressions to have them evaluated.
Type :help for more information.

scala> println("\u3041")
ぁ

scala>

Ok, I will add JAVA_TOOL_OPTIONS on my .zshrc.