PortableApps.com jPortable allows you to easily add a Java runtime environment to your portable device. It automatically works with apps in PortableApps.com Format like Mozilla Firefox Portable Edition. No Java runtime environment needs to be installed on the local machine and no admin rights are required – JARs can be run using our jPortable Launcher
Forcing FirefoxPortable to load Java plugin from ..\CommonFiles\Java\bin
In FirefoxPortable directory (where launcher is located) edit FirefoxPortable.ini and change PluginsDirectory= line:
[FirefoxPortable]
PluginsDirectory=..\CommonFiles\Java\bin