debian/changelog

+tomcat9 (9.0.16-2) unstable; urgency=medium
+
+  * Team upload.
+  * tomcat9.service: Permit read and write access to /var/lib/solr too.
+    (Closes: #919638)
+
+ -- Markus Koschany <apo@debian.org>  Mon, 18 Feb 2019 20:58:51 +0100
+
 tomcat9 (9.0.16-1) unstable; urgency=medium
 
   * New upstream release

debian/tomcat9.service

@@ -39,6 +39,7 @@ CacheDirectoryMode=750
 ProtectSystem=strict
 ReadWritePaths=/etc/tomcat9/Catalina/
 ReadWritePaths=/var/lib/tomcat9/webapps/
+ReadWritePaths=/var/lib/solr/
 
 [Install]
 WantedBy=multi-user.target