Download http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html or copy the Java tar onto your server. I did not find a curl/wget link for direct download, so I used the browser.
Versions may differ. Adjust your script accordingly.
LOCAL:
scp jdk-8u144-linux-i586.tar.gz [email protected]:/temp/SERVER:
sudo apt-get update
sudo apt-get install libc6-i386
sudo tar -xvzf /temp/jdk-8u144-linux-i586.tar.gz -C /opt/
# it will be untarred i.e. into /opt/jdk1.8.0_144, check the folder name for the javaversion
javaversion=jdk1.8.0_144
sudo update-alternatives --install "/usr/bin/java" "java" "/opt/$javaversion/bin/java" 1
sudo update-alternatives --install "/usr/bin/javac" "javac" "/opt/$javaversion/bin/javac" 1
# no webstart on server sudo update-alternatives --install "/usr/bin/javaws" "javaws" "/opt/$javaversion/bin/javaws" 1
sudo update-alternatives --install "/usr/bin/jar" "jar" "/opt/$javaversion/bin/jar" 1
sudo update-alternatives --set "java" "/opt/$javaversion/bin/java"
sudo update-alternatives --set "javac" "/opt/$javaversion/bin/javac"
# sudo update-alternatives --set "javaws" "/opt/$javaversion/bin/javaws"
sudo update-alternatives --set "jar" "/opt/$javaversion/bin/jar"