From http://www.webupd8.org/2014/03/how-to-install-oracle-java-8-in-debian.html

echo "deb http://ppa.launchpad.net/webupd8team/java/ubuntu xenial main" | tee /etc/apt/sources.list.d/webupd8team-java.list
echo "deb-src http://ppa.launchpad.net/webupd8team/java/ubuntu xenial main" | tee -a /etc/apt/sources.list.d/webupd8team-java.list
apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys EEA14886
apt-get update
apt-get install oracle-java8-installer oracle-java8-set-default

Set Java path in MC launcher to /usr/lib/jvm/java-8-oracle/jre/bin/java