I remember wasting a full day on some "permission issue" that was really caused by being logged in as admin:users rather than admin:administrators which somehow doesn't allow the user to run executables.
Just wondering I got 2 nas Ds213j and DS412, Im very interresting in having tomcat and java on DS213j like it is available on DS412.
Is it normal to not be available on bot harware ?
I'm sure Tomcat requires only Java to run, and Java 8 works perfectly on my DS213J so I'm sure it's possible. I can't help with the Synology Tomcat SPK though, but if that doesn't work I'd just SSH into the machine and set it up manually.