FYI: java.io.Writer fixlet from GNU Classpath

[Tom Tromey]

Andrew> I'm wondering what the justification for the Mauve test is.

How does the JDK do on this test?

Andrew> The old Java spec (2nd ed, paper copy) says that "lock" must be
Andrew> non-null, but the current online spec says just "lock - Object to
Andrew> synchronize on."

Yeah, but it doesn't make sense for this to be null.
This is a minor point, but I suppose we might as well be compatible
and throw the exception early if the JDK does.

Tom