Why installing openjdk-7-jdk on Ubuntu Trusty installs systemd as well?

[Yuri Kanivetsky]

Great. Now it all makes sense. Thanks guys.

Yep, with --no-install-recommends systemd is not installed. So systemd
is pulled in as a recommendation.

http://packages.ubuntu.com/trusty-updates/openjdk-7-jdk
http://packages.ubuntu.com/trusty-updates/openjdk-7-jre
http://packages.ubuntu.com/trusty-updates/libgtk-3-0
http://packages.ubuntu.com/trusty/libcolord1 (recommends colord)
http://packages.ubuntu.com/trusty/colord
http://packages.ubuntu.com/trusty-updates/policykit-1
http://packages.ubuntu.com/trusty-updates/libpam-systemd
http://packages.ubuntu.com/trusty-updates/systemd-services

And that explains why debtree and apt-rdepends didn't list systemd as
a dependency. This way apt-rdepends does:

    apt-rdepends openjdk-7-jdk --follow Depends,PreDepends,Recommends
--show Depends,PreDepends,Recommends | grep systemd

And in Virtualbox VM systemd-shim is already installed, so systemd is
no more required.

And after installing systemd-shim, openjdk-7-jdk doesn't pull in
systemd anymore. Which I like more than --no-install-recommends. Since
--no-install-recommends may reject some useful recommendations.