code: public static CharPredicate not(final CharPredicate predicate) {
      return new CharPredicate() {
        @Override public boolean isChar(char c) {
          return !predicate.isChar(c);
        }
        @Override public String toString() {
          return "^" + predicate;
        }
      };
    }
docs: A {@link CharPredicate} that returns true if {@code predicate} evaluates to false.