This changes were used on v8.2.4 in my image:
It´s only for Generic systems. You need the version of java for ARM processors, but I don´t know if its working on the Pi.
Maybe vpeter has a solution for you.
Sorry but vpeter doesn't have any RPi. Which means I'm not looking how to run java there 
Just change init file packages/sysutils/busybox/scripts/init and build the image. It would be easier than changing initramfs in kernel.
And if works with noram then just use this option. This option just disables copying SYSTEM file to ram and mounting from there instead of hdd or sd card or usb stick. Maybe there is very, very small performance hit but you will not notice it anyway.
And set networking in libreelec settings.
Enable kodi debug log and post it.
If I open br with java menu and without my addon I get some notification on screen. Forgot what exactly.
Maybe you don't have br with menu?
In which language?
Not in language but in spam posts.
Because "b o o s t" is usually related to "p e n i s" 
I don't suppose modification of the code could be considered a "feature request?"
I can't answer that. It is easy change which doesn't affect anything else so I would say yes. But other has to say that. Maybe chewitt ?
Does with noram and subfolder works? Because if not then there are more changes needed.
I see. The problem is probably copying SYSTEM file to ram.
Try adding parameter noram to your syslinux or grub. Maybe then subfolder would work.
Look here: LibreELEC.tv/init at master · LibreELEC/LibreELEC.tv · GitHub
If /MYKERNEL works then it should also works with subfolder there.
Try with BOOT_IMAGE=path_to/KERNEL and SYSTEM_IMAGE=path_to/SYSTEM.
It´s working
Was anyone in doubt? 
Variables are set from /storage/.kodi/addons/java/profile.d/java.profile
# needs to point where jre folder is set
export JAVA_HOME=/storage/.kodi/addons/java/
# look for libbluray-*.jar in this folder (with / at the end)
export LIBBLURAY_CP=/storage/.kodi/addons/java/
# or set file directly
# export LIBBLURAY_CP=/storage/.kodi/addons/java/libbluray-j2se-1.0.1.jarSo I added apache-ant, jdk and jre packages and build compete libbluray including jar file which should be part of the image (+760 KB).
The only missing part are few libraries which needs to be build dynamic and not (only) static.
JRE addon almost done too.
Progress: Commits · vpeter4/LibreELEC.tv · GitHub
Can you make a rebuild for LibreELEC-RPi2.arm-8.2.4.img.gz or maybe better..
describe the steps which you take to modify the image and to the rebuild so i do it myself.
It is just cec downgraded to version 3953f8d.
Already building... Will take few hours.
In case it is missed: Add built-in Java support
Wow. How did you do it, only install JRE? Can you wirte a small instruction?
jre1.7.0_04 + libbluray-j2se-1.0.1.jar + few libraries from Ubuntu 16.04
Tested with Milhouse's build #0313, 14-Mar-2018
LibreELEC-Generic.x86_64-9.0-Milhouse-20180314023456-#0313-g9b47b64.tar
instructions: unpack addon in ssh console
wget http://vpeter.libreelec.tv/BD-J/java-br-menu-Generic.x86_64.tgz
tar xzf java-br-menu-Generic.x86_64.tgz -C /
rm java-br-menu-Generic.x86_64.tgzNote to myself: this will need new libbluray*.jar on libbluray bump.
Libraries from Ubuntu could be build on le but they has to changed from static to shared.
Also libbluray*.jar could be build on le but java and ant is required to build. Both could be added as a package (jdk-8u162-linux-x64.tar.gz, apache-ant-1.10.2-bin.tar.xz).