Legacy Portable Firefox to run legacy portable Java only and ignore local install of Java

Question

I have multiple systems that require legacy browsers and Java. I need Portable Firefox to run the Portable Java JRE version and not the Java JRE installed on the OS.

One of these legacy systems is the older HP iLOs console screen which requires Java.

Operating System is Windows 10 Enterprise version 21h2

I have Java 8 JRE update 202 installed locally on the OS for other applications.

The following posts help me get so far:

How to run two browsers (Firefox) with Java plugins in Windows (7) having different versions (1.6 and 1.7)?

https://portableapps.com/node/21946

Portable Firefox version 3.6.28 install location:

C:\PortableApps\FirefoxPortablev3.6.28

Portable Java JRE 6 Update 22 install location:

C:\PortableApps\CommonFiles\Java

Configuration changes made to Portable Firefox and Portable Java:

Moved to following files to temporary folder:

- npdeploytk.dll
- npjpi160_17.dll
- npoji610.dll
- npt.dll

From C:\PortableApps\CommonFiles\Java\bin\ 
To C:\PortableApps\CommonFiles\Java\bin\_backup

Moved the following file:

- npjp2.dll

From C:\PortableApps\CommonFiles\Java\bin\new_plugin\
To C:\PortableApps\CommonFiles\Java\bin\

Edited the file called "FirefoxPortable.ini" located in C:\PortableApps\FirefoxPortablev3.6.28  with following content:

[FirefoxPortable]
PluginsDirectory=..\CommonFiles\Java\bin 

The below will prevent Firefox portable from using the "MozillaPlugins" registry entry.

Open up a new tab in portable Firefox and enter this into web address about:config and proceed further.

Then search and set the following plugin to FALSE

set plugin.scan.plid.all to FALSE

When I launch Firefox portable and in the add in I only see Java 6 plugins:

When I launch the Java application on the portable version of Firefox it uses the Java 6 plugin BUT is using Java 8 JRE not Java 6 JRE:

This causes the application to fail as it is not supported on Java 8 JRE update 202 but I can confirm if the PC only has Java 6 JRE update 22 the Java application functions fine.

For some reason Java 8 JRE update 202 is still being used.

Is it possible to force Firefox portable to run Java Portable JRE and not the local install of Java JRE?

Update 1

The below URL show it is possible to do a offline install on JPortable version 7:

https://ryanwintaraga.wordpress.com/2013/02/10/how-to-install-jportable-offline/

I don't know if this is progress but as I am on closed internet network I was installed JPortable on my personal PC and copying folder CommonFiles\Java and all sub-folder within Java to the PC I have the issue with.

So I decided to try version jPortable_7_Update_13_online.paf and I downloaded the JRE file jre-7u13-windows-i586

I put both files in a folder (this allow offline installation) and went through the install process on my closed network PC and made the same file changes as above and re-tested on the browser.

The difference here is I get a warning stating my Java is out of date (which is a good sign as it is using portable Java JRE update 13 for the first time):

Then after selecting the option I get a pop window for my app and after some time the browser crashes (no warning or error messages before it):

UPDATE 2

After more research and testing installing the JPortable Java JRE 6 Update 22 on my personal PC with internet connectivity and copying the folder from personal PC to another (with blocked internet access) or installing (PC with blocked internet access) JPortable Java JRE 7 Update 13 with the jre-7u13-windows-i586 file in the same install folder doesn't make a difference JPortable works both ways.

Answer 1

After much testing and researching I found the problem that is causing the local Java 8 JRE to run in the Java 6 plugin.

If you navigate to the following folder (depending on how you installed JPortable):

C:\PortableApps\CommonFiles\Java\bin

Select file javacpl.exe (I suggest right click with and "Run as administrator"):

Select Yes on the User Account Control message:

Now the JPortable JRE 6 Update 22 Control Panel should pop up on the screen:

Select the Java tab and the select "View...":

Now you should see the JRE's JPortable is able to access.

This next step is important

You need to untick the box "Enabled" for the Java 8 Update 202 or whatever you have installed then select "OK"

Then select "Apply":

You may get this warning select "OK"

Now when I re-try and run the Java application on the legacy portable Firefox it works fine:

The problem was I didn't know any other version/versions of Java installed on the same PC have there own Java Control Panel setting stored in there own folder - I assumed the latest version of Java would take precidence over all older versions of Java installed on the PC so if you made the change in the Java control panel for Java 8 JRE Update 202 this would push it down to other version of Java - THIS IS NOT THE CASE

I believe you still have to disable legacy portable Firefox from searching the whole PC for addons for this to function.