Just for the record (and completeness): the + operator will work on String, but will not perform addition (like with two ints), but concatenation. So for all primitives (except boolean) the + is an arithmetic operator for addition (and that's including chars!), and for Strings it's a concatenation operator for (obviously) concatenating.
Pop quiz question time! Do you know the output of this code snippet? And "yes" or "no" is not a valid answer