What is the format of regular expressions in SonarQube?

Question

I'm trying to set the mutable exception coding rule in SonarQube, but it requires a regular expression and any standard regular expression I give it results in:

Validation failed: Value 'regex' must be a regular expression

Google had no results for "regular expression sonarqube" either, so I'm at a loss.

Answer 1

It's a Checkstyle rule. See http://checkstyle.sourceforge.net/config_design.html#MutableException. This is a regular Java expression and there is supposed to be a validation of the regular expression when you click on "Update".