How to disallow a digit repeating n times with a regular expression

Question

Here is my @Pattern annotation. I want to disallow digits that repeat 9 times. What have I done wrong?

@Pattern(regexp="(?!.*\\d{9})")

These would be invalid strings:

111111111
222222222

These would be valid:

111111112
222222221
123456789

Only strings with a length of 9 will be valid but this is not needed as part of the regular expression since that will be controlled by other annotations.

Answer 1

Edited following the comments

I think you meant you don't want the same digit repeating 9 times. To do that, you need to capture one digit, and refer to that and see if it repeats for 8 more times.

@Pattern(regexp="^(?!(\\d)\\1{8})")

If you simply use \\d{9}, it will mean repeatition of any digits.

Note also that you don't need .*. Regex will decide where to start the match on its own.