I think the simplest way to update an ES is to download the lastest 32 bit ARM Java 8 SE from Oracle (121 as of this writing), copy it onto your MangoES and move it to /usr/lib/jvm/, then
tar -xvzf jdk-*.tar.gz cp -rf jdk1.8.0_121/* java-8-oracle/ rm -r jdk1.8.0_121 rm jdk-*.tar.gz #Edit: On newer ES units, you need to give the new java executable permissions to the ports below 1024, like, setcap 'cap_net_bind_service=+ep' java-8-oracle/bin/java #sudo or root setcap 'cap_net_bind_service=+ep' java-8-oracle/jre/bin/java #sudo or root
apt-get is handy, but this will work for almost any ES. For older ES's the JDK may be installed in /opt/jdk and never under the management of apt. In that situation, one could do almost the same thing, only
cp -rf into the old JDK's directory instead of java-8-oracle/
I was able to apt-get install oracle-java8-installer on an ES, these seem to be the pertinent entries in /etc/apt/sources.list (but I personally may still do it manually so that I don't have to believe its dependency list)
deb http://ppa.launchpad.net/webupd8team/java/ubuntu trusty main deb-src http://ppa.launchpad.net/webupd8team/java/ubuntu trusty main
Edit: To worrying about manual configuration, that's why I take the lazy man's route of overwriting the files in the existing JDK. All of the installation type steps are just making symlinks to this or package management. If you use apt it will handle all that for you. If you overwrite the old Java it'll already be set up. But, if you install Java into a different directory, you'll have to do some update-alternatives commands to get /etc/alternatives/java (and javac, javaws) to point to the right file.