Comment 8 for bug 1307883

I'm seeing this same issue on a minimal Ubuntu/trusty chroot, where I deliberately didn't want initscripts and upstart installed. Using minimal chroots is very useful for running automated build infrastructure. The chroots can serve as stand-ins for full systems or VMs. Since the base system provides the whole system, including daemons, init, etc. the chroot does not need this stuff, and indeed it can get in the way.

This worked before, since I was able to set up this chroot a while back and use it. I think I set it up around Sept 2014.

Here's the error:
Setting up openjdk-7-jre-headless:amd64 (7u71-2.5.3-0ubuntu0.14.04.1) ...
/var/lib/dpkg/info/openjdk-7-jre-headless:amd64.postinst: 18: /var/lib/dpkg/info/openjdk-7-jre-headless:amd64.postinst: mountpoint: not found
the java command requires a mounted proc fs (/proc).
dpkg: error processing package openjdk-7-jre-headless:amd64 (--configure):
 subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of openjdk-7-jre:amd64:
 openjdk-7-jre:amd64 depends on openjdk-7-jre-headless (= 7u71-2.5.3-0ubuntu0.14.04.1); however:
  Package openjdk-7-jre-headless:amd64 is not configured yet.