I tried following up on that sentiment, and it appears your assumption is actually wrong:
At any rate, I'm using an unmodified sun-jvm straight from my package manager on linux. Among the other top hits on google are mentions that even Mac OS defaults to non-UTF8 encoding, although MacRoman will probably act less violent about non-ASCII characters. Even a default install of a commercial grade tool like Maven will by default complain about character encoding, and I think we just figured out why.