I was able to get this running, albeit not perfect on a QNAP NAS not using the prebuilt x-19 or intel packages for QNAP.
I did this by installing the JRE-ARM package, and the TOMCAT server package from QNAP.
Then I downloaded the WAR archive from the madsonic downloads site and deployed via TOMCAT manager.
I did this all by following this site and using google's translate function.
(replace locations and folder names of subsonic with madsonic)https://www.brainmauke.de/?p=272
it has a how-to for deploying the WAR into tomcat but it's all german.
Anyways... my problems are as follows:
Changes to the installation are not persistent. When I change the admin password it works until the app is restarted in tomcat. When I add media folders and index the music, it's fine until after restart, then the path is no longer there.(likely permissions but not sure where this is stored or how)
Also can not find transcoders... i put them in /var/madsonic/transcode/ and restarted the app, still no go. Also there is a lock file created in the DB folder that is not removed.