Well, my server crashed again this morning. After doing more searching, it appears this is a known and relatively common problem with the Sonos binding and the old version of Cling library that it uses. I’m going to start investigating how to fix this, starting with upgrading the upnp library to the latest version. In the meantime, I may write some rules to stop the bundle during the night when we aren’t using the Sonos. In the worse case, I’ll just remove the Sonos binding until I or someone can find a fix.
As an aside, it’s slightly impressive that a RPi 2 Java process can be running 5000+ active threads before it dies.
Here are some links to related discussions. I was surprised that I could find no open issues related to this problem. If someone knows an existing issue number, please let me know. Otherwise, I create one in the next day or two.