Error in the regex capturing groups example.

[saltos]

Chapter Identifying field values to mask by value contains invalid example for the capturing regex groups case.
In the example you use "\1" as the group reference but it does not work. We should use a dollar sign as a reference. Please look at java.util.regex.Matcher documentation.
I've spent some time wondering why "\1" does not work for me.

[philsttr]

Fixed. Thanks for the report!