Brought to meta on the basis that it's too drastic a change to make unilaterally or on the basis of three people discussing it in the comments of a different question...
- You cannot use digits in your code (0123456789);
- You can use any language in which digits are valid characters (so that not using them is a real restriction);
That second restriction is really badly worded, but it does indeed seem to be intended as "You may only use a language in which digits have meaning (so that not using them is a real restriction)".
The problem is that this tends to push towards a forked situation where we have two questions which are identical apart from one not having the restriction (or inverting it, to avoid either being a technical dupe of the other). That's silly. And really the restriction seems silly too: if a language doesn't use digits to represent numbers, it's probably sufficiently verbose that the 100 character limit is a more painful restriction than avoiding digits is for Java.
I propose removing the language restriction, leaving the digit use restriction (and adding the tag restricted-source).