Install Java to start with. Then proceed with an old school Firefox as follows.
To get Java plug-in to work into firefox you need an older version: v52 ESR (not latest release). AND YOU ALSO NEED TO PREVENT IT FROM UPDATING ITSELF TO ESR 60,
cd ~/opt/ #wget https://download-installer.cdn.mozilla.net/pub/firefox/releases/52.4.1esr/linux-x86_64/en-US/firefox-52.4.1esr.tar.bz2 #tar xjf firefox-52.4.1esr.tar.bz2 wget https://download-installer.cdn.mozilla.net/pub/firefox/releases/52.9.0esr/linux-x86_64/en-US/firefox-52.9.0esr.tar.bz2 #rm -rf firefox tar xjf firefox-52.9.0esr.tar.bz2 cd firefox/ rm -rf update* ./firefox -no-remote #--ProfileManager
Also disable updates from the Settings,
Tools > Preferences Advanced // Update // Never check for updates
Deploy the Java plugin,
cd ~/.mozilla/plugins #cd /usr/lib/firefox-addons/plugins/ ln -s /usr/lib/jvm/java-8-oracle/jre/lib/amd64/libnpjp2.so
Weaken the crypto requirements
Start menu > Oracle Java 8 plugin control panel Start menu > Oracle Java 9 plugin control panel
or
jcontrol
or
ControlPanel
then
security > add exceptions e.g. http://localhost:xx (the port number matters)
To get to the Java console of e.g. some old enterprise-class servers, a quick and dirty fix would be,
updatedb locate java.policy #cp -pi /usr/lib/jvm/java-8-oracle/jre/lib/security/java.policy /usr/lib/jvm/java-8-oracle/jre/lib/security/java.policy.dist #vi /usr/lib/jvm/java-8-oracle/jre/lib/security/java.policy cp -pi /etc/java-8-oracle/security/java.policy /etc/java-8-oracle/security/java.policy.dist vi /etc/java-8-oracle/security/java.policy cp -pi /etc/java-8-openjdk/security/java.policy /etc/java-8-openjdk/security/java.policy.dist vi /etc/java-8-openjdk/security/java.policy grant { permission java.security.AllPermission; };
Linux 64-bit installation instructions for Java https://www.java.com/en/download/help/linux_x64_install.xml
Java Downloads for Linux https://www.java.com/en/download/linux_manual.jsp
9 Manual Installation and Registration of Java Plugin for Linux https://docs.oracle.com/javase/8/docs/technotes/guides/install/linux_plugin.html
Oracle Java Archive https://www.oracle.com/java/technologies/oracle-java-archive-downloads.html
Java 8 Release Highlights https://java.com/en/download/faq/release_changes.xml
Java 7 Release Highlights https://java.com/en/download/faq/release7_changes.xml
Java SE 7 Archive Downloads https://www.oracle.com/java/technologies/javase/javase7-archive-downloads.html
Java SE 6 Downloads https://www.oracle.com/java/technologies/javase-java-archive-javase6-downloads.html
How to install the Java plugin for Firefox? https://askubuntu.com/questions/354361/how-to-install-the-java-plugin-for-firefox/354406