public void setLocale(Locale locale) {
        this.locale = locale;
    }
This should be a valid IANA language subtag (e.g. en, en-GB, de, etc).

@see <a href="https://docs.oracle.com/en/java/javase/17/docs/api/java.base/java/util/Locale.html">Java Locale</a>
@see <a href="https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry">IANA subtag registry</a>
@param locale the user's preferred locale
manager/api/beans/src/main/java/io/apiman/manager/api/beans/idm/UpdateUserBean.java