Hi Paul, Thank you very much for reporting this issue. I confirm this happens when purging the package only. The offending chown was first introduced in the tomcat6 package 6 years ago  as part of the fix for #567548. The same issue is also found in the tomcat7 package.
Do you think running something like "chmod -R 640 /etc/tomcat8" right before the chown is an appropriate solution to this issue? Emmanuel Bourg  https://anonscm.debian.org/cgit/pkg-java/tomcat6.git/commit/?id=f67781f __ This is the maintainer address of Debian's Java team <http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/pkg-java-maintainers>. Please use debian-j...@lists.debian.org for discussions and questions.