The easy way is to use Internet Explorer (ie) as your browser as it still allows Java
There are 5 steps quoted: 1) Making Webmin File Manager Work (Opening Java Control Panel)
in win7 type into the start menu "comfigure java" ( its target is "C:\Program Files\Java\jre1.8.0_231\bin\javacpl.exe" )
2) Step 2: Making Webmin File Manager Work (Open Java Security Tab)
and then click on "Edit Site List...".
3) Making the Webmin File Manager Work (Adding an Exception to Java for Webmin)
add your server IP and Webmin port thus https://yourPBXip:9001
And now click on Add, and close the Java Control Panel.
4.1 ) Opening the Webmin File Manager (Activate Java Hurdle)
In the Webmin menu open the "Others" branch; here you will find a line saying "File Manager" but that is the html5 version.
You want the "Java File Manager" Ugh! Ugh you probably updated Webmin only to find the "Java File Manager" is missing.
4.2 So you need to install Webmin Java File Manager the file is https://download.webmin.com/download/modules/file.wbm.gz
So now still in Webmin "Others" branch you can open "Upload and Download" and then open the
"Download from web" tab
and in "URLs to download" type
Download to file or directory: /root
Owned by user: root Now click "Download URLs"
So now you can find the downloaded file at /root/ but no hurry to look -
From Webmin menu now open the "Webmin" branch and select "Webmm Configuration" then
open "Webmin Modules" select the radio box From local file: and type into the box
and click "Install Module"
5: Opening the Webmin File Manager (Last Hurdle?)
In short when the Java warnings pop ups from a browser, you will need to allow Java to Run while selecting
the "Do not show this again for apps from the publisher and location above" (or like warning dialogs).
Now why bother with it? Well the Java File Manager just makes life a lot easier especially searching for text occurances in multiple files, extensions*.conf; looking for instances of "Language = en " and do multiple cut and pastes. On the other hand you could learn to grep and the like.