Ubuntu – How to install Firefox 32-bit ESR 52 without uninstalling Firefox 64-bit on 16.04


My computer has Ubuntu 16.04.2 LTS 64-bit and Firefox 52 64-bit.

For one of the government web sites, because it is using browser Java plugin to sign documents, I need to install:

  1. Firefox ESR 52. Ordinary Firefox 52 does not support Java as browser plugin anymore, because NPAPI was removed (source).
  2. Firefox ESR 52 32-bit. I know for sure Firefox 32-bit only supports Sun Java on Windows, but not sure if this is also a limitation on Ubuntu. If it is, I need Firefox 32-bit version and not Firefox 64-bit version. 2

I know I can install Firefox 32-bit like using:

  1. install Firefox 32-bit in terminal:

    sudo apt install firefox:i386

    but installing Firefox 32-bit will uninstall Firefox 64-bit, which I would like to keep.

  2. download and extract Firefox 52 ESR 32-bit from 2.

Is there any other was to install Firefox ESR 52 32-bit and also install Sun Java 32-bit on Ubuntu 16.04.2 LTS 64-bit without uninstalling Firefox 52 64-bit?


  1. Plug-in support has been dropped other than Flash
  2. Download Firefox Extended Support Release


Best Answer

Please try this workaround. For me, the plugins like Java and VLC came back after doing this. I'm using Ubuntu 16.04 64 bit with Mozilla Firefox 64 bit version 52 (not ESR) and Java JDK 1.8.0_112

  1. Open Firefox and type about:config in address bar and press enter
  2. Click 'I accept the risk!'
  3. Right click anywhere and select New>Boolean
  4. Type plugin.load_flash_only in the box that appears
  5. Set the value to false
  6. Clear all history and restart Firefox

I'm also using various Government websites which uses java plugin and Digital Signatures.

Try this and let me know.

Edit: Mozilla Firefox 53 will remove the flag plugin.load_flash_only so that this workaround won't work anymore.

Pale Moon web browser team announced that they will continue the support of NPAPI plugins indefinitely. To install java plugin in Pale Moon, run this in terminal

sudo ln -s /usr/lib/java/jdk1.8.0_121/jre/lib/amd64/libnpjp2.so /usr/lib/mozilla/plugins/libnpjp2.so

I've tested java plugin in Pale Moon browser. 100% working.