Unwanted install with apt-get remove
Solution 1:
To get more space in /var/cache/apt/archives/ run sudo apt-get clean.
Apparently you have some PPA added offering Oracle Java as alternative Java engine; run apt-cache rdepends --important --recurse --installed openjdk-8-jre-headless to find out what is the reserve dependency. If there is none such dependency, you could try --no-install-recommends with apt-get purge. If there is a dependency, you could remove that, or disable the PPA offering Oracle Java.
Using sudo apt-get autoremove will remove unneeded dependencies, too.