The Strings class (note the trailing "s") in core is going away.
If you used Strings.join(stringIterable, separator) replace it with stringIterable.join(separator).
If you used Strings.concatAll(stringIterable) replace it with stringIterable.join().
The old methods are now deprecated and will get removed in a few weeks.
// florian
--
Give a man a fire and he's warm for the whole day,
but set fire to him and he's warm for the rest of his life. - Terry Pratchett